I noticed today that NWN 2 has been announced. It's slated for a March 2006 release.
It'll be published by Atari and developed by Obsidian (the developers of KOTOR II), based on Bioware's engine.
NWN 2's official forum (if you have suggestions for the game, you can make it there!):
http://nwn2.obsidianent.com/