I've got a new 27" iMac within the past couple of weeks, and have connected the 22" monitor to it that I was using before I got the iMac (I was originally using a 17" MacBook Pro notebook connected to the 22"). Plenty of screen space for eve (at 1920x1200 resolution), Tweetie for Mac next to it (Twitter program), Chrome browser on the other screen, with my chat program next to that.
Sometimes I get a sore neck from swinging it back and forth to see what's happening on both screens... It's a hard life, I tell ya.
A closer view.