An actual great Elder Scrolls game
There isn't too much variety in the gameplay, since Oblivion is your typical hack 'n' slash RPG game, but there is a ton a variety in the thing to do. Aside from ramparting through many dungeons to kill goblins, crabs, bats, and the like, you can take on quests from villagers, complete tasks set by the guilds you join, roam the huge map looking for places and things to do, etc. There is a lot to do. Some stuff is tedious and repetative however. Building your stats can be a pain, but it's fun. The different customization options are great. There are hundreds to choose from.
Graphics:
The best on the 360, and some of the best I have ever seen. The game is amazingly beautiful.
Sound:
The music is reptative (a whole 2 tracks or so), but it's good, and never really gets old to listen to. The voice acting is top notch, for the most part.
Replay:
With many classes, a variety of guilds, and a bazillion things to do, Oblivion has very high replay value.
Overall:
A must own for 360 owners. This game is very addicting and immersive, and leagues above the other Elder Scroll games.