In my opinion this is the greatest game ever made, the people at Bethesda should be really proud of what they created. I played 140 hours on this game and my advice to anyone reading this is buy this game now, your life won't be complete untill you own it.
This game allows you a sense of freedom I've never found in any title other than Morrowind the game before Oblivion in the Elder scrolls series.
Graphically this game is beautiful, the landscapes or huge and well formed and I recently hooked it up in HD and it looks even better.
The main storyline is engrossing and one of the best parts of this game are that the side quests are as well formed as as the main plot. You can join several guilds the fighters, mages, theives and assassins guild (dark brotherhood), each of these guilds are like a game in themselves, with well rounded plots, unique prizes and great characters.
I would now list the bad points of the game but I must honestly say there aren't any so I won't bother.