hey, i want to do a graphics card upgrade, but i'm not sure what else i would have to upgrade, or i need to upgrade anything other than the graphics card (i'm open to other upgrades). I game a lot, and would like to continue to do so with the newer titles coming out, like call of duty, and grand theft auto 4. My budget would be between $300-450. Any help would be greatly appreciated.

Processor: Intel Core 2 Duo E6550 2.33 Ghz 4MB Cache 1333 Mhz FSB
Motherboard: Asus P5K-SE Intel P35 + ICH9 Chipset
Memory: 2x 1GB PC5300 DDR2 667Mhz
Graphics: ATI HD 2600 XT 256MB PCI Express Graphics Card
Hard Drive: 500GB 7200RPM 16MB Cache
Optical Drive: 18x DVD�R/RW Drive
Sound Card: 8 Channel High Definition Audio
Chassis: Premium Mid Tower with 500W
Operating System: vista
Monitor: 24" acer

You wouldn't need anything else, unless the PSU's +12v rail amperage can't handle a new, more powerful, graphics card. I would, at the moment, recommend the Radeon HD4870 or the HD4870x2. Both cards have more than enough power for the newest titles but require a lot from the PSU. If you wanted to wait a little longer, the HD4850x2 is due out soon and I think AMD claims it beats out nVidia's GTX280. You just need to make sure that the cards would physically fit in the case, for they are 9+ inches long. An HD4870 goes for well under $300 at the moment and some are even less than $250!

Okay thats good to know, thanks alot for replying so quickly, im still not sure which i will choose, but at least i know i can upgrade with little trouble.