I like Newegg myself. Oh and zipzoomfly.com is good too.

I don't know all the technological mumbo-jumbo, but I did do a lot of comparing before settling on a processor. Basically, I just learned that AMD is better than Intel. Also, I learned that a single core (FX-60) could be the fastest processor on the planet at doing one thing (gaming), but that most of us do different things (check email, listen to music, rip a dvd, whatever). Thus, most of us would benefit from dual core. I don't know why it works better, but the fact is that it does.

I rip two dvds from two drives at the same time. I play Doom 3 while ripping mp3s off of a cd and downloading on bittorrent. No slowdown. The processor cost me about 500 bucks though. There are cheaper, better value AMD dual cores though. I just don't like overclocking, so I got one that I wouldn't have to.