I've come across a couple of issues with 3.0. The main ones that I think have to do with wordpress itself are:
1. I can't upload a new photo - technically, when I click to add an imagine, the upload screen loads up in the same window, instead of a hover. I can upload the photo, I just can't insert it as doing so times out the site.
2. I thought maybe re-installing it would fix, but I can't find the upgrade link under tools. Is it supposed to be there?