Sometimes it pays to read the Key Bindings listing. Today I found out that ⌥⌘` (or ⌥⌘~) toggles between the main editor window and the project drawer. Since I use the Subversion bundle heavily while in TextMate, being able to switch back and forth between the two contexts is great.
Another tip that I never knew about was the “Edit in TextMate” command (installed via the TextMate bundle) that works with most programs on OS X (I use it mainly in Mail.app, although I tried it on the WordPress editing window in Safari to write this post). I clicked in the form field, hit ⌃⌘E (Control+Command+E), and it launched an editor window in Textmate. Probably not worth the hassle for short posts/emails, but for longer writing stretches it’s nice to work in the environment in which I spend the most time. Saving in TextMate dumped the text back to the input form in Safari (although only when that window is in focus). This is all very geek-tastic.