I agree with mar77a. If you want fast (wireless N is 74mbps), and reliable (all wireless will eventually drop or accept some form of interference), best chance is with cable. I had done wireless for the same reason and ended up just buying a really long cat 5 cable. The lower ping times, dropped packets, and random disconnects were just too much for me and all my online gaming.
I'd like to give some good recommendations on wireless hardware, but N just came out and I have no real experience with it. As for B/G, I think the WRT54G is a great choice. Lots of good open source firmwares available for it too, if you're into heavy customization.