Hell, I just go with whatever's the fastest at the time of purchase. Sometimes it's intel, sometimes its AMD. the last time I upgraded, it was AMD (4400+ X2). Before that I had a p4 2.53GHz, and if I were to buy now, it'd be a Core Duo.
However, vid cards, I always go with nvidia. ATi is such a pain in the ass with driver problems, glitches galore....and now their latest cards require ginormous amounts of power? no thanks.