I bought a Kindle Keyboard when it was the only Kindle, and for now it remains my only Kindle. But I have been wrestling with that question myself ever since the Kindle Touch was announced. I have not come to a decision at this time.
Looking up words is more important to me than taking notes, but I must admit that after watching Lisa's video review, I'm starting to rethink whether the Kindle Touch is really what I want. I don't like the lack of hardware page turn buttons - it makes me think the screen will quickly get covered with fingerprints, negating the clarity of an eInk screen. Also, I thought the lack of keyboard would make it drastically smaller and lighter than the Kindle Keyboard, but it looks like maybe not so much.