Haven't seen these mentioned yet, but may have read too quickly:
Kitchen scale (I like my cuisinart digital one)
Good pepper grinder (I bought my unicorn one after asking a waiter what kind his was, when I was impressed by the amount of pepper that came out with each grind).
Probably my favorite kitchen tool is my thick maple cutting board. I'm tall enough that it feels much more comfortable to use the thick one instead of a thin one. Stays on my counter (too heavy to put it away each use), and looks nice there, too.
A couple of heavy duty sheet pans.
This one is 13 gauge aluminum, and is the one that won the Cook's Illustrated test for sheet pans in 2007. I use mine constantly.
Oh, and get a couple of Silpats (or similar) for them.