If you are looking forward to testing out the new 3D interface for Ubuntu in their upcoming release, you have only a few months to wait. The interface, which requires you to have certain proprietary software (such as hardware accelerated graphics drivers), was a bone of contention for many, but found to be worth inclusion. However, it won't be configured as the default interface as originally planned, due to concerns over software maturity. Given that their aim is to provide a desktop that is not only functional, but stable, their justifications are sound.
They also pushed the PowerPC release of Ubuntu back, moving it into an "unofficial" state. If you're using a Mac, don't hold your breath for that release.