(with type tool selected) Option + Click. If you know you need a column of text that is a specific number of pixels wide (or tall), this can be a faster solution than using your guides and rulers.
Highlight Text in Layer
Double Click Text Layer Icon. This is one I haven’t yet incorporated into my workflow but seems helpful. Double-click the “T” in the layer palette and all the text on that layer will highlight, then make desired changes.
Close Text Box
Command + Return. Close a live text box. This one’s nice because simply hitting return will just add a line break to the text – d’oh! Pressing esc and losing the changes you just made isn’t really helpful either. Hit cmd + return, and then you’re free to jump over to the Move Tool or whatever else you might want. (Props to Ethan for this one – I’m pretty sure he mentioned this one the other week.) *Update: If you’re using an extended keyboard, simply pressing the enter key will also close the text box. Thanks to all the commenters who pointed this out!
Command + Shift + K. This can be a quick way to toggle caps for any text. It’s the same thing as hitting the all caps button on the Character panel. Pretty straightforward.
Command + Shift + </>. This can be helpful if you’re just bumping the text down one point size or if you’re wanting to get a feel for the sizing on the fly. Hitting option as well will change the font size by 10pts instead of just 1pt at a time.
(with text highlighted)Option + Left/Right. Increases the spacing between all the letters in the highlighted area.
Option + Left/Right. I’m assuming most people use this one already but a necessity if you’re kerning some headline text.