1680x1050 and 1280x1024.
Eventually I'll have to get matching screens, but the size/resolution difference doesn't bother me (I use 1 screen for email, IM, the big one for what I'm working on, which, depending on how many windows it opens up, may span the other screen). And when I worked from home I used 2 PCs so had 4 screens, and still there is not enough screen space!