Oblivion was vast and filled with things to do, but lacked detail. Dungeons were frequently copy-paste jobs, the enemies you faced were only those appropriate to your level, and everything felt...uniform.

Skyrim fills in that detail, and that's the most noticeable and praiseworthy thing about it to me. Locations are unique, encounters depend on where you are and what you're doing, and NPCs will change their comments to you based on your skill levels and what weapons you're carrying. Exploration is a joy instead of a grind.

The other bits are still very good, mind you. The plot is enjoyable and interesting, and there's a lot of extra flavor in the guild and side quests. The only major gripe I have is the way that Enchanment, Alchemy and Smithing are handled; because the improvements that Enchantment and Smithing offer are skill-based now, and you can't hire anyone to improve things for you, you're almost always required to level them yourself, despite them being different "playstyles"

Excellent mechanics with a great setting; so many over-the-top characters and hilarious antics. Each class is distinctive and the game isn't short, making for good replayability. The Knoxx and Zombie DLC are also absolutely top-notch and should be appropriated immediately.

If you enjoy playing Diablo II by yourself and getting into the character creation aspect then you'll love Titan Quest. Many character classes provide countless combinations to try, and the whole game is set in a lush Grecian setting filled with characters and places straight out of mythology.