If you're in the United States, you can get get couplers, wall jacks, and cables at a pretty good price at compunettech.com. Had all the Cat 6 stuff that I was looking for, and pretty cheap, too. (I was recently asked to re-wire my parents' house, and after doing some searching, this was the lowest-priced place I could find). Shipping's reasonable and fairly fast. Worth a look if you're having trouble finding Cat 6 inserts (their Cat 6 stuff cost almost the same as their Cat 5e stuff, so I went with Cat 6 all the way--future proofing, I guess
But to echo the other posts here, I don't think it'd make much difference at all. Your computer system would act at the major bottleneck, and although I never picked apart a Cat 6 jack and a Cat 5e jack to see just how they are different, I somehow doubt that there would be much difference at all.