What video card can i use for my custom desktop?

ok i have a custom desktop i know these things about it i have a intel dual core 3.2 ghz processor, a 160 gig harddrive, 2 gigs of ram, and a 550 watt power supply, already has updated sound card, i want a nice video card but im not sure what to get or what it can hold anybody know ???|||PCI express graphics card, ie if your pc has apci express slot. Nvidia 9500 512MB or higher will be just fine.