I don't like to knock DVDboxoffice. Most of the time I have used them they delivered quickly. But because they don't show stock availability, you are effectively shopping blind. Thats what I put down to their lack of delivering anything to me the last two times I used them (for advance wars 2 and FF Tactics). So I gave up.
I tried play-asia recently and they are pretty good. Videogamesplus get a good write up, and also importmadness.co.uk (might help avoid customs?)