Wow... Big game... So mutch to do, and so little time :D
The game is huge... You have a main quest and this is okay... But!
You can do other quests, to get peoples trust.... Many interesting quests, many sad... and many funny quests.
You can join guilds like the fighters guild... You can also join the brotherhood there you kill people for money and get rankings like the other guilds..
There are plenty to explore, caves, castles and old ruins.. You will often find treasures like gold, pearl, diamond and stuff..
You can also offer gifts to different gods, when you have offered them a gift that they have asked for... then will they give you a quest, after you have done the quest. They give you a rare item for your kindly help.. This game is simply amazing, the forest with animals, flowers and enemy. You can either walk the hole way from a spot to another... or just click at the map where you will direct go too, I like to walk. You find more places like caves and castles... And you finds more quests by walking in the Oblivion world..
The graphics are good.. The ps3 version looks nicer but its worth to take a look at... Rent it, or better.... Buy it !!! ;P