Surprised by how good it is.
I really wanted to like Morrowind, but I just couldn't get into it. The storyline seemed to take forever to get going and just dragged on, I couldn't really get into the "feel" of the world, etc. Oblivion on the other hand starts off very well - I was able to get into the storyline right away. Although gameplay is MUCH more important for me than graphics, I have to give Bethesda major props for the visuals and sound. The level of detail in this game is stunning. The voice acting is exceptional, which is great because an RPG succeeds or fails based on the storyline and characters - the characters in Oblivion seem very real to me - the voice acting isn't cheesy or over the top.
At the end of my first day of playing the game, I have nothing but good things to say about the game. Good job Bethesda! Hopefully some of the other developers will learn a thing or two from you about how to make a great game and realize that a great-looking game does NOT mean it's necessarily a good or "next-gen" title if the gameplay stinks.