New monitor recommendations?

Quick question about picking up a new monitor. What would you guys recommend for gaming if I'm looking to spend around $500? My setup is running an ATI Radeon HD4890 on an mb ASUS MA770-UD3—though if that motherboard part is right, I'm not totally sure since I haven't messed with hardware too much. Not sure if modern LCD monitors need specific slots or anything like that :P
Thanks in advance, and sorry if there's already a dedicated thread for this kind of stuff.

Apple iPhone or the T220—they're basically the same thing, though obviously the T220 is a bit bigger