Bethesda Softworks will release The Elder Scrolls 5: Skyrim on November 11, which is still more than a month away. I'm not sure this newly released list of Xbox 360 Achievements will help or just make the wait harder, but the list is here all the same.
I wouldn't call anything on the list a serious spoiler, though specific quests are named in the bulk of the descriptions and you may want to proceed carefully. From what's listed, we can infer that a sizable faction-based choice is made at some point in Skyrim (think Shivering Isles). It also looks like the level cap falls at 50, since that's the last level-based cheevo.
Check out the full list at Xbox360Achievements.org.