Before you purchase Hordes of the Underdark, or even patch your original game to 1.69, be advised that your performance will be cut in half.
The original NWN campaign has the best performance of all the NWN series; just go to [URL="http://nwn.bioware.com/downloads/linuxclient.html"] and follow the instructions. NWN game data is given to you for free! Just get the large 1.1 gb file and the smaller 5mb file, follow directions (no need to patch until you run into bugs) and keep your game as the original campaign. Remember that you NEED an original legitimate CD key, so go ahead and buy the copy of the game (it's bioware, come on, you know they deserve it).
Performance of HotU (NWN platinum install) in ubuntu is 16 fps max indoors
The original campaign, same locations? 30 fps indoors.
If you want to play NWN, you must ask yourself: What do you value? Performance and playability? Or extra content, spells, etc?
Be sure to edit your ini files, as well, to keep graphics options low.
Best of luck to you all!