Bethesda just released the beta version of the patch for Oblivion. If you're feeling adventurous, you can try it out right now. But be advised that it -being a beta version- may not solve all problems as advertized and may introduce new ones. So, if you don't have a serious problem, you may want to wait.
Bugs fixed include various engine bugs like the famous crash-on-exit bug, various quest bugs as well as bugs that can happen when using mods. Additionally, a number of performance enhancements have been made, for instance for users of SLI and CrossFire.
Oblivion Patch v1.1.425
Patch Notes / List of bug fixes and enhancements (at the bottom)