A must for OS X converts
One of the biggest changes to get used to in switching from Windows to a Mac is some of the different keyboard shortcuts. Some things like Command-C instead of Control-C for copy/paste is easy to adjust to, but others like how the home and end keys work are totally different.
On Macs, the home and end keys will go to the begining/end of document, however I still desire a way to easily go to the beginning/end of a line. I use this plenty when posting online, writing emails, and even coding. You can do Command-Left/Right to do the same, however if you are typing in a browser, doing Command-Left will also navigate away from the page, basically losing everything you just typed. Never like that.
Luckily, you can fairly easily change the keys behave like you're used to Windows. Just create a file in /Users/[username]/Library/KeyBindings called DefaultKeyBindings.dict (create the folder if not found) and change the keys as you like. I copied the first blurb in the "Examples" section of this page. Or, here is another more thorough example.
One thing to note is that the changed key bindings don't work in Firefox or Camino, so the Control-Left is still there, but it does work in Safari... but then in Safari, seem to run into issues with WYSIWYG editors on many sites (yes, including Community Server and Graffiti). I'm not sure whether or not I love or hate Safari.
PS: This post was written in Safari with proper functioning home/end keys (ahh, heaven). The key to using it is to remember the site is expecting HTML.
Update: The next beta of Graffiti will support WYSIWYG editing in Safari according to this. The current Beta1 release doesn't support it, though.