I have a 24" TV which I use as a monitor(samsung) and I prefer playing my games in widescreen rather than 1920x1080
Isn't 1920x1080 a 'widescreen' (16x9) screen resolution? Or you like the black bars??????
GTX 460 (OC'ed to 850, mine can get Crysis almost maxed at 1920x1080 with an average of about 24fps)
ATI Radeon 5850
ATI Radeon 5830 (Should be able to cut it at that rez)
The new ATI cards are a little iffy as they are about 10.5" long. With a new card, make sure you fill all of the fan slots, and blow around the case to get rid of the dust.