MotB (expansion 1) is very unique and fun, one of the best RPG campaigns of the decade.
Neverwinter Nights 2 has a decent campaign (better than vanilla NWN1 campaigns) and two fantastic expansion campaigns. Not sure how you connect to them nowadays, though. I think some of the multiplayer servers are still up, existing beyond the Gamespy server browser's demise. Hordes of the Underdark (expansion 2) is the best of the three, but it is not 'great.' NWN1's best feature is its large modding community, there's a great deal of user-made campaigns available on IGN's Neverwinter Nights vault. The Shadows of Undrentide (Expansion 1) campaign has a neat character (Deekin!) and is sorta enjoyable. The base campaign is not very good at all. Neverwinter Nights 1 has rather poor campaigns. There are things to be enjoyed about both games.
