one of my friends picked up a cheap 5700 for £50, it'll run all of these games at around medium graphics, if you want to spend more you can get the 9600xt for 70-80 quid depending on where you shop. If you want to spend more i'd go for the 6600gt, nice card and runs half life 2 at full on an amd athlon 200xp system with a gig of ram