This is a fantastic game. Graphics and sound are amazing, and I constantly found myself just wandering around the HUGE game area marvelling at it all. I played this game for about 25 days straight (completed it after 20 and just kept going) and although most of the fights become easy once you get to the higher levels, thats when the expansion packs come in :D. The level up and skills acquisition system for this game are probably the best I've ever seen - the ability to learn skills be reading certain books, as well as by being trained by NPCs throughout the game is something I've never encountered before.
And I haven't even mentioned the storyline yet. This could have come right out of a fantasy epic (Robert Jordan's "The Wheel of Time" series springs to mind) and adds a whole new depth to the gameplay.
The only thing that could improve this game imho would be multiplayer capability, but if it was a MMORPG I dont think I'd have bought it, so I'm not too upset about that.
If you haven't played this game yet, what are you waiting for? I believe the GOTY edition is now available, so you can get Bloodmoon and Tribunal at the same time, for the added fun