Yeah, but even if they're DRM-free Amazon can still take them away - http://news.ycombinator.com/item?id=4682392
Until they offer a cast-iron, legally-binding guarantee that any ebook I buy from them cannot be taken away from me, they don't get my money.
If I buy a book, it's my book: If the bookshop I bought it from takes it back, then that's theft.
As far as I'm concerned, the same holds true for ebooks. I buy it, it's mine. Period. Until Amazon agrees with me, I don't buy their ebooks. It's that simple.