Snip
Resolution - this in many ways is the most important, but the one that probably is irrelevant to you. The higher max. res a monitor can go, the better (sharper) the picture quality, however
all 22 inch monitors are 1680 x 1050 resolution, so there is no need to look at this.
I would add though that your 4850 card is easily good enough for this resolution (ie powerful enough to run all games at full detail), and even in fact for most at the higher 1920 x 1200 resolution found on 24" monitors.
This
viewsonic 22" is good value at £152.
The
£196 Acer 24"er's have been around for a while (
reviews here), although given how much cheaper that is than most 24" monitors i suspect that you get what you pay for.