I updated WordPress yesterday, so am currently trying out 2.3, Dexter. No major dramas, all, really thanks to the Automatic Upgrade plugin, which I’ve been using recently (second WordPress version it’s upgraded).
One annoying bug, was seeing: WordPress database error: [Table 'wordpress.wp_post2cat' doesn't exist]. If only I’d read the release notes before hand, I’d have realised the Google Sitemap plugin was to blame (there’s also a relevant forum post). Disabled that (for now) and all is well. There’s some slick in-built tagging, so I’m using the web interface to write this (something I haven’t done in a very long time).