A+
Pros:
-Incredibly fun and engaging combat gameplay
-Great character development system
-Amazingly detailed open ended world
-Music is incredible
-Graphics are beautiful
-Quests are engaging
-Totally engulfed in the varying quest threads - main quest, civil war quest, guild quest
-Fun side quests that are more than just "go kill 10 bears for me" - some of the funnest side quests I have ever played
-Fun, challenging dungeons that often times require some thought to get past them.
-Spell casting is FUN
-Loving the perks system (I guess that fits under character development system)
-Love seeing the inclusion of the Smithing skill, love seeing Enchanting make a return.
-A true sense of journey and adventuring when I travel from one place to another (no fast travel for me!)
-I love companions, and having someone accompany me on my journies, even if I keep getting them killed

-The world certainly does "feel" bigger than Oblivion's, which helps out with that sense of journey and adventure
-Different environments, from the snowy mountain ranges, to the streaming rivers and open plains. Just a beautiful world
Cons:
-Minor bugs. Nothing gamebreaking, but certainly noticeable.
-I do miss certain spell effects, like summoning ghosts, liches, wraiths, skeletons, etc... as well as Command spells.
-Really short guild quest lines.
-I think that's all I can think of.