If I'm not in a hurry, I can get OEM parts cheaper than most chinese junk parts from Rockauto.com
But if I'm in a bind, I go to Advanced usually. In my town, we got Advanced, Napa, Autozone, and ORileys all within a 1/4 mile of eachother.
Each store has their own niche for me. I usually get my parts (anything from brakes, distributors, suspension, etc.) at Advanced. I try to stay out of AZ. ORileys usually carries the better oils and additives.
Napa can get me anything, if I'm willing to pay. They are usually quite a bit higher than the other three.
But Rockauto has the best deals I've found.