Help to straighten this Old Fart re: Monitor!

Well, for the best display quality, you want an S-PVA or S-IPS monitor. These are difficult to find in 22", but many of the better 24" panels use these (the cheaper panels use TN, which is noticeably worse in display quality). However, you will pay quite a premium for the S-PVA or S-IPS type panels - a couple examples are the Dell Ultrasharp 2408WFP ($600ish, depending on whether it's on sale) and the HP LP2475W (also $600, sometimes more). If those are completely out of your budget, then there isn't a huge quality difference between cheaper 24s and 22" monitors, although the 24" panels will look a bit sharper due to the smaller pixel pitch.

A 4870 1GB and a 24" TN would be a decent setup then. I'm not as familiar with the various 24" TN panels though, so I can't give any specific recommendations.