I see that 20.5 inch screens are down to about $120.00 - what should I look for when buying? I will be using it for gaming.

Yo Grimjack.

It depends how large the sreen size you want to be or what's your budget. Do you have any brand or model in mind? There is a link about the top gaming monitors.

Another guide about how to choose a good gaming monitor. See this

http://www.gamingreviewguide.com/monitors/

I use the Samsung PX2370 gaming monitor. Because it support mac as well, cos i use it. PRice about $220+. Not sure whether you want it. Most monitor i seen are above $200 and above. What model and brand is the gaming monitor.