alibris: They won't let you know how much shipping will cost until they've already charged your credit card, their customer service is non-existent (this one I've experienced directly -- I asked for clarification on a listing where the language and publiser info didn't match, and got nowhere), and I've read too many horror stories about people having trouble obtaining refunds for items that turned out to be out of stock. My guess is that they're fine for straightforward mainstream transactions, but I've got amazon, abebooks, and powells for those.

I do like microwaveable pizzas, but I have next to zero freezer space right now. Hence the adventures in just-add-water. ;-)