I saw a 8600 gt at the store and I considered buying it but what do you think should i get the 8600 gt 9600 gt or some other nvidia video card?

Upgrading one part of your system generally means you need to upgrade multiple parts of your system.

Find out this first:

How much graphics card can your processor handle?

Motherboard?

Power Supply?

Definately don't get the 9600gt....it has a lot of problems and is not that big of an upgrade from the 8800 series and you'll spend about $600 on one when you can get an 8800GT for $250 or less.

If you're using Vista, it's a good idea to get a graphics card/motherboard/processor that all support direct X10 graphics.

If you're not worried about directx10, just go for like a nvidia 7000 series or something. It dependson what games you want to play. Future games are moving into the directx10 range, but a lot of games out there right this second still only support 9.