John Joyce wrote:
Honestly, I haven't met a Ruby book I didn't like yet.
I have, but it was so bad I've forgotten which one it was. 
No, seriously, they're all mostly good and despite the large amount of
overlap, there's room for a few more. But the Pickaxe is a must have for
just about everyone, and I think AWDR and Ruby for Rails are both must
haves for Rails developers.