With a superior story to its predecessor and an improved party system, NWN2 is a must buy for fans of the original.
The storyline is much better than the original which could be a serious drag at times. That's not to say that this is perfect as it is quite slow to get going, but it is a big improvement. All the depth of the Forgotten Realms is still here, as well as the great dev tools and the amazing community. The graphics are good, with great spell effects, but some disappointing character models and textures. The sound is good with a great soundtrack, but you will definitely hear character sounds and spell incantations repeated ad nauseum which can really grind on your nerves. Some of the voice actors really got on my nerves as well, although they were quite good for the most part.
One of my favourite improvements in the game is the overworld traveling system. It is nice to not have to walk for extended periods of time through empty environments, and I found it did very little to disrupt the game.
All in all, a very solid RPG and a worthy sequel. Here's to a third.