Omo asks what stores people use.

For R1 DVDs I go to RACS, although I bought an item or two from AnimeNation and TRSI. My Vandread set came from DVD Pacific, a bargain-hunter's outfit. RACS offers competitive prices versus specialized retailers, and although the likes of DVD Pacific are unbeatable, the difference after the S&H is small enough for me to exchange it happily for the RACS's consistent service.

For R2 DVDs and J-pop I use CDjapan. I have only one R2 DVD which was not bought there: Manabi Straight Special (it comes from Amazon.co.jp).

P.S. Forgot to add, but I make some purchases in brick-and-mortar stores. For example, I bought Naruto Uncut v.4 in Borders. Mostly it is Fry's, who devote a lot of shelf space to anime. But physical transactions are infrequent these days. No matter how much shelf Fry's is willing to allocate, RACS's warehouse is bigger still.