Must Have!
The graphics is excellent, the leaves on the trees, the grass, the details on the weapons is just that damn good! The best graphics you can get on a Xbox 360 game in that genre this period of time.
The sound is perfect, very good quality.
The gameplay is also very good, with an intensive main quest where you save the whole world of Tamriel. You also have other quests (missions) for different guilds you encounter in the game.
I can't wait till Elder Scrolls V comes. When it comes (sure hope so :)) it has very big shoes to fill! Cause Oblivion was a very good game!
Buy it, enjoy it!