Note that it has handy links to reviews of some of the cards. Any of the cards you listed should provide excellent gaming at 1280x1024. When you say your monitor only exceeds that resolution, does that mean you play at higher resolutions and if so what?
Upgradevideocards.com is a good general reference for upgrading. It has information about reviewing personal and system requirements, links and information about video card reviews and installation, and also some guides on using other sources including those at THG.
I prefer nVidia cards right now because they are way ahead of ATI/AMD on Phsyx for gaming and using the video card to assist the CPU on parallel processing functions, both of which I think will be adopted by more applications because of the substantial peformance benefit. So from your list I would go with the GTX 460. In particular, I would go with the EVGA video card at $160 after rebate: