Books you can't get in ebook form: Yeah, that's still a problem. Tor keeps telling us that nobody buys their ebooks which is why they don't focus on their market. I believed that until my brother pointed out that his favorite authors are all being published by Tor, and none of their books are available in ebook form. Hm. Somebody needs to grab Tor's tail break that spin cycle for them ;-)
Cost of ebooks: has come down. In most cases seems to consistently be slightly cheaper than paperback now, as opposed to halfway between paperback and hardcover last time I looked. This honestly is still a rip-off -- the publisher's costs for an ebook are a fraction of their costs for publishing and distribution, but honestly as long as it isn't more expensive I am game.
Cost of ebook reader: this is still a factor. $280 is a lot of books :-( However I have found a free ebook reader named Aldiko for my Android G1 that I really like. It has a great download feature with lots of good science fiction for free, so I'm going to give it a real try over the next few weeks and report back.