Oblivion Patch Causing Issues
The much anticipated patch for Oblivion is here, but it has come at a cost. 1up reports on complaints from users about lockups, lagging, and some curious technical problems. From the article: "Even though the patch cleans up a number of glitches quests, many are still upset because it doesn't solve their existing issues. If you've already run into and experienced a glitch quest, there's a good chance the patch will do nothing to fix it; the patch can't fix contaminated saves. Consequently, Bethesda employees have been recommending fans start new characters if they want to experience these quests."
Most highly open-ended games are like this. Think of how difficult it would be to play test a game like Oblivion versus a typical FPS.