H ere's a tiny adjustment to Xcode that made me happy. Using the app-specific keyboard shortcuts (System Preferences » Keyboard » Keyboard Shortcuts » Application Shortcuts) to make your workflow a touch quicker / more convenient. If you have a smaller keyboard, the key combos get more cramped and hard to remember, but I was just noticing how unused these higher function keys generally are. I'm sure you can suggest even better helpers. Of course, season to taste. [Insert standard rant about the lack of tear-off menus in OS X…]

I should also add that you can edit source code files with other programs if Xcode is missing some feature that you really want to use at some moment. For instance, TextMate has a number of features up on Xcode that are very handy, like block code editing, many clever shortcuts and macros. Xcode will note the changes as they're saved by another program.