I shop around. I have had some rotten experiences with Tiger, but their warehouse is 10 miles away, and if I order something from them, I often get it the next day without paying for 1-day shipping. That’s makes them worth dealing with despite their sins.
Newegg is very good for almost anything mainstream. Best Buy should be burned to the ground and the ashes hauled off to a toxic dump.
This place
http://www.etech4sale.com
is good if what you’re looking for is in stock. They deal mainly with closeouts and refurbs, so you can get very good prices if you’re lucky.