I've only bought one book from Amazon so far --- but then again, I haven't received my Kindle yet. It *might* get here about Valentine's day. I'm stocking up on free books, so far.
I've been using my Palm devices for ereading for 10 years, however -- and I have over $1000 worth of books I've bought at ereader.com. SO ..... when I catch up reading the tail end of those, I"ll be buying from Amazon full steam. I love romances and mysterys.