What is the best graphics card available for this computer that won't bottleneck the CPU?
Specifications: 2GB DDR2 (up to 4GB max). Intel Pentium 4 CPU with HyperthreadingT @ 2.8GHz overclocked to 3.4GHz stable. Runs Fedora linux. 1 PCI express x16 slot (shouldn't be a problem, PCI express x16 2.0 is backwards compatible). ASUS P5KPL-CM motherboard. I could install a Pentium D 3.0GHz for $25 and I can always upgrade the PSU to accommodate a more powerful graphics card.
I need the most powerful graphics card I can get for the computer that won't bottleneck it. Below are some pictures of the computer (they are the parts from my parents' old computer that I recently upgraded; the computer runs great, I just don't have a case for it yet)