We're getting really close to the next release. It's going to be 1.5.1 as it's synced against WP 2.5.1 and it makes sense to follow the minor version number at least.
I'm going to be putting this on a live server tomorrow morning, and I feel quite confident that it's not going to blow up on me. Then again, if you do the same, don't do it for the next 8 hours. I'll be asleep and unable to help you!
Grab the latest code from Trunk at http://trac.mu.wordpress.org/browser/trunk?rev=1275
There's a zip file link at the end of the page for easy access.
Hopefully if nothing shows up tomorrow we can call it 1.5.1 on Friday and finally get it into the hands of the less adventurous among you! (or sensible, depending on how you view these things)