At any rate, over the few years of using a Mac, I’ve picked up a few tips and tricks that others might find handy.

Tips and Tricks
Here are a few non-obvious things you might want to know about:

Don’t ever buy .Mac. You can do most of this stuff for cheaper per/mo with Dreamhost. I haven’t messed with Back To My Mac screen sharing (Apple just use VNC) much yet, but still it seems like a waste of money.

One of the things that I’m still trying to get used to is the application grouping with Apple+Tab. What you have to do is hit Apple+Tab to get to the application you want then Apple+` (next to the 1) to cycle through that applications windows. This grouping gets especially irritating if you try to use Spaces.

Function keys
By default, you have to push the function key + an F# key to activate the F#. This can be changed in System Preferences->Keyboard & Mouse.

Locking your screen
In Linux, I would bind Scroll Lock to lock my screen for me. In OS X you can’t do that. What you have to do to make it remotely easy is either set up a hot corner to run the screen saver (I always activate it by accident with my wild mouse movements) or go into Applications->Utilities->Keychain Access->Preferences and check the “show in tray” check box. This will put a lock next to the clock and give you a menu that has a Lock Screen option on it.

Adding external speakers to a MacPro:
If you plug speakers into the back of a MacPro sound will still come out of the internal speakers. To make external speakers work, you need to go to System Preferences->Sound and just click “Line Out” then close the window.

Connecting to VNC/VNC server:
If you want to connect to a VNC server, in the Finder Menu (click the desktop) click Go->Connect to Server and type in vnc://host. At the same time, if you want to run a VNC server on your Mac, go into Apple->System Preferences->Screen Sharing

SSH (SFTP) Server:
If you want to start SSH, go to Apple->System Preferences->Sharing and check Remote Login.

Applications
I’ve tried to hunt down beautiful and functional applications that meet my needs on OS X. Here is my list. I would love to hear if you have any extra’s to add.

Terminal
If you’re in a pinch, you can find Terminal in Applications->Utilities->Terminal…
but you probably need a better Terminal if you’re going to be spending any time in it. iTerm is a pretty good alternative to the default OS X terminal. The settings for iTerm are weird. Click Bookmarks from the menu bar, then Manage Profiles. Choose xterm on the keyboard layout and change delete to send hexcode 08 and set Option key to +Esc. You can change the Display Profile if you want. Now go to Bookmark->Manage Bookmarks. Select Default and change the Keyboard to xterm. This will make the keys work the way you expect them to especially with screen. If you use vim, add set term=xterm to your ~/.vimrc to get that to act normal. (Note: The Leopard Terminal.app seems to be a lot better, but I still prefer iTerm.)

If you end up sticking with Leopard’s Terminal go to Preferences->Settings and click Pro then click the default button. Now click the keyboard tab on the same screen check “Use option as meta key”. Now click the shell tab and select “Close the window” under the “When the shell exits:” heading. Finally click advanced and check “Delete send Ctrl-H”. I would also clean out some of the bindings in the Keyboard section.
iTerm: http://iterm.sourceforge.net/

Deskbar Applet
Gnome has a widget toolbar thing called Deskbar that is like Windows version of Start->Run on meth. Quicksilver is the OS X version. I have nothing “stuck” in my dock and I launch all of my applications using Quicksilver. Usually what I do is disable the Spotlight key bindings in the System Preferences then bind Quicksilver to Apple+Space.
When it first opens, push Apple+, to get into the preferences and check “Show icon in menu bar” and “Start at login” then uncheck “Show icon in dock”. This is a cleaner way of running Quicksilver.
Demo: http://www.43folders.com/2007/09/05/quicksilver-demo-by-nicholas-jitkoff
Quicksilver: http://www.blacktree.com/

Web Browser
Safari is alright. Webkit is the application framework for Safari. If you’re like me, you prefer Firefox and it’s plugins.
Firefox: http://www.mozilla.com/en-US/firefox/
WebKit: http://webkit.org/

FTP/SFTP Client
Cyberduck, to me, is the best client. It supports FTP, FTPS, and SFTP. When you first get this, be sure to go to Preferences->SFTP and set the Transfer using option to SCP. This ends up being faster.
Cyberduck: http://cyberduck.ch/

MP3 Player
I’ve for a long time tried to find something like Winamp/XMMS for OS X. There are a bunch of old unmaintained applications but you should just get used to iTunes. Sorry.
FLAC/OGG/Others support: http://www.xiph.org/quicktime/download.html

IM
Adium is the best IM app. It’s based on libpurple, the same library Pidgin (GAIM) uses. It ends up being a lot prettier than Pidgin too. Note: When you install Adium it will ask if you want to install Growl. You should agree to it. Growl is a system page that a lot of applications use. It’s very nice.
Adium: http://www.adiumx.com/
Growl: http://growl.info/

E-mail
For a long time I used Thunderbird but ever since Leopard I’ve embraced Apple’s Mail app. If you decide to do this, you might need to tell Mail to use your server’s Sent mail folder by going to Mailbox->Use This Mailbox For->
Thunderbird: http://www.mozilla.com/en-US/thunderbird/

Bit Torrent
I like Transmission the best for downloading torrents for some reason. The vanilla Bit Torrent client is comparable to Transmission for downloading and far superior for creating torrents. I end up downloading/seeding with Transmission and creating torrents with the vanilla BitTorrent app.
Transmission: http://www.transmissionbt.com/
Official BitTorrent: http://www.bittorrent.com/download

Simple video conversion
iSquint is nice and free. It has an older brother called VisualHub. I ended up buying VisualHub and not regretting it. If you want to unencrypt and copy the original DVD there is a program called MacTheRipper that can be tricky to download but Version Tracker probably has mirrors.
iSquint: http://www.isquint.org/
VisualHub ($): http://www.techspansion.com/visualhub/
MacTheRipper: http://www.mactheripper.org/ (version 2.6.6 http://www.versiontracker.com/dyn/moreinfo/macosx/22715)

Rar Files
UnrarX is nice. BetterZip supports everything (7z) and costs money. I’ve gotten by with just UnrarX because OS X comes with support to untar/zip/gzip/bzip files.
BetterZip ($): http://macitbetter.com/
UnrarX: http://www.unrarx.com/

PDF Viewing
Preview works fine but Skim has support for annotating on the PDF and such. I like this feature.
Skim: http://skim-app.sourceforge.net/

Note taking
Circus Ponies Notebook costs money but seems pretty nice and very pretty. I haven’t had the need to take many notes so I haven’t had to play around with this. It might be handy if you wanted to go to school.
CP Notebook ($): http://www.circusponies.com/

Office stuff
OpenOffice has OS X stuff. They recently made it OS X pretty. I use MS Office 2008. If you want an editor that gets all the distractions out of your way WriteRoom costs money and does a pretty good job at that.
OpenOffice: http://porting.openoffice.org/mac/
WriteRoom ($): http://hogbaysoftware.com/products/writeroom

Calendar
Sunbird is cross platform and Mozilla. I use and like iCal. If you setup SSHFS or WebDav it’ll give you .Mac-esque publishing.
Sunbird: http://www.mozilla.org/projects/calendar/sunbird/

WMV stuff
Flip4Mac will make WMV stuff work. It has a browser plugin too (that works for Firefox).
Flip4Mac: http://www.flip4mac.com/

Video playback
VLC plays anything.
VLC: http://www.videolan.org/vlc/

SSHFS
There are some free alternatives that seem flakey to me. ExpanDrive is really nice. It costs money but it seems like it’d be worth it if this is something you do all the time.
ExpanDrive ($): http://www.magnetk.com/expandrive
I didn’t like this: http://www.pqrs.org/tekezo/macosx/sshfs/

Last.fm
They have a official OS X client. It had some bugs in Leopard. I ended up buying the MacHeist bundle and got CoverSutra. It’s not free but works really well at controlling iTunes via keyboard shortcuts as well as submitting tracks to Last.fm. Hopefully official client bugs are fixed now. If you don’t want to use either I ended up using iScrobbler for quite some time.
Last.fm Client: http://www.last.fm/download/
iScrobbler: http://www.last.fm/group/iScrobbler
CoverSutra ($): http://coversutra.com/

Virtualization
If the only thing you want to do is run Windows apps, maybe Parallels is better. If you really want to do virtualization VMWare Fusion is the way to roll. I say just stick with VMware. They’ve been doing it longer.
Parallels ($): http://www.parallels.com/
VMWare Fusion ($): http://www.vmware.com/products/fusion/
P.S. Vmware is beta testing 2.0 right now. It’s kind of broken so download the 1.0 trial and use the 2.0 beta key. It’ll give you a trial until Oct 2008.

Version Control
Leopard comes with SVN. I’ve since moved to Git.
GIT: http://code.google.com/p/git-osx-installer/downloads/

Source Editing
I have a hard time with this. Most editors are cross platform (Komodo Edit, Netbeans, etc). I haven’t used Apple’s XCode much but people like it and it’s on your install CD. TextMate is the editor all Mac programmers will tell you is the best. I use it. It has some nice features. It also costs you money in the form of British pounds (it’s about *2 in dollars. Thanks Bush).
Textmate ($): http://macromates.com/
Komodo Edit: http://www.openkomodo.com/

Encryption stuff
GPG is pretty standard.
TrueCrypt is cool. It will create an encrypted volume for you and mount it like a regular drive. I downloaded some different icons for my encrypted volumes and I assign a different color to each one. This is probably an old find, but I’m just now jumping on the bandwagon. At work (this can work for OS X) I sym link my Mozilla and Pidgin settings and logs to my truecrypt drive and unmount it when I go home. I like the idea having all that stuff encrypted.
GPG: http://macgpg.sourceforge.net/
TrueCrypt: http://www.truecrypt.org/

Uninstalling Applications
Mac people will always tell you “Just drag the app to the trash and it’s uninstalled”. They’re half right as it technically is uninstalled. In OS X an applications is just a folder with a .app extension. It has some of the libraries it needs inside that folder. What it doesn’t have is all the settings and some of it’s extra libraries in it. AppDelete will hunt that stuff down and delete it for you. It’s a free alternative to the prettier AppZapper.
AppDelete: http://reggie.ashworth.googlepages.com/appdelete
AppZapper ($): http://www.appzapper.com/

Information Manager
I’ve only tried one and I haven’t gotten used to it, but Devonthink Pro seems pretty nice. The idea behind this app is a personal knowledge base. You catalog and categorize everything you find and it builds a database based on your cataloging so you can search for information later. It’s one downfall is the lack of syncing between computers. To solve this I created a (4gb) TrueCrypt volume on an 8 gig thumb drive which I mount and read the database from. This app is a niche app and costs money. (DT Personal comes with MacHeist2 and won’t let you specify database files. You can only have one.)
Devonthink Pro: http://www.devon-technologies.com/products/devonthink/index.html

Twitter
I’ve only tried twitterrific and it does a pretty decent job. Costs money or free with advertisements in the update window.
Twitterrific: http://iconfactory.com/software/twitterrific

Well, there you have it. I’ll probably end up making this a page rather than just a post and I’ll try to update it as often as possible.