My post asking about one 30" monitor or two 23" monitors generated quite a few comments. After reading The Large Display Paradox, it seems like I should either find something like WinSplit Revolution for the Mac, or get 2 monitors. I agree with everything that Jeff Atwood says about maximizing windows, that's why I originally thought two 23" monitors might be better.
It worked ok with 2 17" LCD monitors but did have some issues with most games... One thing to keep in mind is that it may not have the bandwidth to drive anything over 2x1280x1024.
I don't play games (too addictive), but if I can't drive both monitors at 1900x1200, it's probably not worth it.
So you're getting a 30" monitor then?
Maybe, but there's a problem with the 30" that I didn't think of: I'd need dual video cards in my Windows box to drive it. Not only that, my KVM switch probably can't handle a 30" monitor. If I'm wrong, and I can drive a 30" monitor through a single DVI KVM switch, let me know. In the meantime, I'm strongly considering a single 23" with my MacBook Pro on an iCurve next to it. That gives me dual monitors when I'm on the Mac, but not on Windows. That's OK - I don't use my Windows box that much anyway.