The X600 I got for $25 will play CSS and thats all I would ever need to play over the lan
weeelll.. I'm talkin about BF2 kinda demanding games. So I'd say like a 7900GS or a little weaker would do. I'd want it to last a little while for her.
its too bad they don't have weaker Dx10 cards out yet for cheap, lol.