As has been mentioned elsewhere, WordPress 2.0 is in beta. We’ve kept it low key so far, but we’re getting a pretty good testing turn out nonetheless. Several little bugs have been shaken out since the first beta. If you are feeling adventurous, try it and share your beta experience in the Beta Forum or on the Testers List. As always with unreleased versions, don’t use it on your live site just yet. If you do, make a backup and be ready to rollback.
To keep track of bug fixes going into 2.0, watch the timeline. We’re fixing bugs pretty briskly and releasing new 2.0 release candidates as we go.