Might buy a copy if there is some great stuff in there but its a tough call with WordPress books. I think the WordPress plugin development book that came out recently was a good, long lasting book (ie won't be obsolete the next time WP releases a new version with new interface). If WordPress Bible can pull that off it would be worth a buy.

Personally I'd love one of these publishers to sell a PDF version that you get say 6-12 months free revisions for so that you get the edits for whatever new WP versions come out in that time. For PDF distribution I would even say they could edit and release a new revision within 30 days of a new WP release.