First, a helpful warning: Do NOT buy this game for the included game campaign. Instead, buy it for the amazing network play, customizability, the toolkit, and the community-created adventures and modifications, some of which are absolutely marvelous.
The included game campaign is far, FAR from perfect, but it still isn't nowhere near as horrible as most people think it is. It is average, has rather unamazing plotlines and - well - isn't quite as thrilling and polished as the Baldur's Gate series, or other respected CRPGs. There aren't too many really memorable scenes in it, and somewhat too many less interesting quests, but overall, it left a good taste. Not as good as the competition, but good anyway.
Yet, the community creations are already getting FAR more interesting than the included campaign, so there's not much to complain. And Bioware's later NWN releases - the Witch's Wake module and Shadows of Undrentide expansion - show also that the game isn't as worthless as the critics of the game say.
The game itself is graphically more than decent, the gameplay works wonderfully, and the included toolkit and netplay features definitely make it interesting enough. The game has great potential: The toolkit allows people to create their own adventures, which is always a good thing, especially since the toolkit is powerful, easy to use and well polished, not just a hacked-together pile of trash that was added as an afterthought. The only obstacle is that most complicated things require some programming skills, but this is being remedied (plot wizard in the newest patches, script wizard from the community).
I recently also got the expansion pack Shadows of Undrentide, which contains (based on cursory playing) a FAR better game campaign with some rather interesting ideas. If you haven't got this game already, get it along with the expansion. You won't regret it.
I heartily recommend this game to everyone who is tired of merely consuming entertainment and would also like to (at least try to) be creative. 10/10