First, a couple thoughts on the original game:
I found Dungeon Siege to be extremely addictive. I suppose the lack of loading screens did contribute a bit to that. There's always the push to go just a little bit farther.
Having said that, the gameplay could be extremely frustrating at times. If you want a half-decent nature mage in your party then you HAVE to take them off on their own every now and then and level them up, just so they can catch up with the rest of the party. Like a previous poster said, magic was pretty much crap until you get to the end of the game - and since experience gain is based on how much damage a particular character is doing (not shared among your party), your mages are pathetic unless you babysit them.
The other lousy part about the game (sorry GPG, it was lousy) was the complete lack of RP in this RPG. Surely there must be some balance between a NWN style game and DS?
A few more pros: you have NOT seen this game until you've played it with some 3D glasses
A feast for the eyes. And the sound is amazing.
However, I can't say I'm terribly enthusiastic about Dungeon Siege 2. It's not that I don't think it'll be a fun game - it probably will be, and I'll probably buy it shortly after it comes out. But... Dungeon Siege 2 means that I'm going to have to wait that much longer for Chris Taylor to start working on the spiritual successor to Total Annihilation. The original TA offered some of the best gameplay the RTS world has seen.