For those of you looking for alternatives to buying books at Amazon, I recommend
Abebooks (or their
UK,
Canadian,
German, etc sites) which is a website that thousands of smaller booksellers use to catalog and sell their books.
You can look up just by book or go specifically to your local shop's page.
Here, for example, is the link to Uncle Hugo's (the oldest independent science fiction bookstore in the US) and Uncle Edgar's (the mystery bookstore that adjoins it) which happen to be my favorite bookstores.
Eta- A different Amazon,
Amazon Bookstore Cooperative in Minneapolis (founded in 1970) is the oldest independent feminist bookstore in North America (although after being sued they will be changing their name to True Colors Bookstore)
Eta2-
karaokegal mentioned another good online source for books is
http://www.alibris.com/. Eta of eta-
phoenix64 mentioned, as an FYI, that this site tends to charge a lot over and above what the bookseller is asking.
Eta3- abebooks might be owned by Amazon.com now. Even so the local booksellers still would profit from your using it.
eta4- Another bookseller-
Powell's from Portland, Oregon has an extensive online site.
Eta5- Also check out
Indiebound, formerly known as BookSense.