As a few of my readers have pointed out, SixApart (the people who own TypePad and Movable Type, which run my blog) are a bunch of greedy little things. The links to the books at left on my list of recent reading contain a SixApart affiliate ID. Thus, if you buy one of those books (or a book that you found through that link), they'll get a small piece of the action. Sadly, my only way to disable this feature is to set up my own affiliate ID, and I'm not really interested in that.
I've bought from Amazon many times before. They're not the only bookseller in the game, though. I also recommend chapters.ca, as they have a few advantages over Amazon. First of all, I can use my 10% iRewards discount card there, as I can at their retail stores. This often leads to a lower overall price, as they actively compete with Amazon. Secondly, you can search the inventories of their stores. This often lets you get a book sooner, and saves you the shipping cost. Note that their sales online do not necessarily match their sales in-store, so pricing may be different.
My real favourite, though, is the Advanced Book Exchange. This is a network of small bookstores around the world, mostly in used books, that works together to provide an online catalogue and online purchasing. This is great, because you can track down rare, out-of-print, non-mainstream, used, signed and whatever other kind of books you want. I've found them to be quite reliable in the past, and they're always my first stop when looking for a book. One of their best features is the "Wants" list. You can specify a search, and the catalogue will email you when a book matching it is added.
So if you're going to buy a book I read, try ABE first!