I have my eye on some bigger monitors, but I just haven't pulled the trigger, yet. Probably when I build a new computer I'll step up in monitor. In addition to doing all my work in front of a computer screen, I play a lot of racing simulators, so something a little better might give me an egde and make for a better experience.
I think I'm waiting for a good reason to build my over the top Vista PC. Sadly, I've yet to find a really good reason to upgrade from XP.