The Elder Scrolls IV:Oblivion is not all as great as everyone claims it is.
First of all, after you do all of the guilds, and the main quest, the game can get pretty boring. Not much to do but walk around killing random people. I have restarted the game about three times now because I got bored at about level 15. The game will amaze and keep you that way for the first 15 levels, but after that, everything is the same.
And secondly, what most people do after about level 15 is train. However, I find this quite boring. I would rather go do a quest. The only problem is that you do all the good quests by this time. So, you either stay bored or restart, which also gets boring after a few times.
I must conclude that Oblivion is an amazing game, for the first 15 levels. After that, I find that it gets boring. For that, I do not give it a 10, nor a 9, but an 8.5.