What is the best video card for my emachines t3104 computer?

My computer has a AGP 8x slot and the max 2 gb of RAM. I'm unsure of the power supply andI have Windows Vista Ultimate 64x bit Installed.|||If its only has an AGP slot, you're better off getting a new computer as that computer is so old and shoddy that simply replacing the video card won't get you the performance you're looking for. Emachines are extremely low end and typically not worth upgrading at all. Even if you could somehow put a $500 video card in there (probably more than you initally paid for the entire computer), it wouldn't make it a gaming computer.