First of all, the graphics are breathtaking. Superb lighting effects, great 3D models, impressive textures.
Second of all, the voice acting is just right, transporting you in the virtual world of Tamriel.
The next game of the Elder Scrolls series keeps the races and classes from the previous versions, and adds great features such as horseback riding (present in Daggerfall, but removed from Morrowind) and an active cross-hair showing the health of the NPC (or monster), the possible actions with the NPC, and if it's OK to use an object or not (it turns red when you look at an object that's the property of an other NPC).
The new combat system is just great, with the option of manually blocking an attack, and being able to cast a spell even if you have weapons / shields equipped.
The story (with it's flaws) is perfectly integrated in the world of Tamriel and there's loads of books and scrolls that add to the Elder Scrolls lore.
The bad things...
The leveling system is a great idea, but it still allows you to turn your character into a "jack-of-all-trades". I mean there's actually no problem for your orcish character to sneak around pickpocketing people and braking into the NPC's houses, or to become a heavy armored, axe wielding wood elf.
The requirements for this game are rather high, meaning that you need a high end system to play it. (Kind of restrictive, huh?)
The story: You were a prisoner back in Morrowind. Come on, can't you guys come up with another setting for the start of the game?
The Bottom Line
This is like the ultimate single player RPG. If you enjoyed the previous Elder Scrolls titles, you should play this game. As for all of the game's problems, they'll surely be solved by the massive Elder Scrolls community through mods, just like the previous title, Morrowind.