I play in a NWN persistant world, and there are plenty of them around. The one I play on is run by a friend, who now lives in Europe (I'm in Australia), so it's a good way for us to keep in touch.
But also, I run a campaign with 5 players and all of them play on that world too. As do several other ppl I regularly game with.
Our worlds has tradeskills, ie, you can be a leatherworker, and make bags, leather armour, etc, you can make metal weapons & armours, and even arrows and bows. This all adds a lot of flavour to the game, as you personalise the development of your PC.
Also lately we've been playing specific modules using NWN once a week or so - old 1st Ed modules, some new ones. These have all been played without a DM, and have been pretty good (some better than others - try U1 (Sinister secret of saltmarsh), for a very well implemented module for starting characters.
Anyway, I'm spending far too much time playing NWN atm
