Well, the RC for the latest version of the Ubuntu Linux distro is available! You can get Ubuntu 10.10 RC (Maverick Meerkat) now. You may want to check out the known issues first though. They do consider this a stable RC ready for all though.
[...] we formally announce Ubuntu 10.10 Release Candidate. Codenamed "Maverick Meerkat", 10.10 continues Ubuntu's proud tradition of integrating the latest and greatest open source technologies into a high-quality, easy-to-use Linux distribution.
We consider this release candidate to be complete, stable, and suitable
for testing by any user.
Here's the announcement email.