First of all, it's great to see the reference to hack. I feel the love. Second of all, I don't see how ppl can really compare DS w/ NWN. I'd recommend NWN only if you really love D&D. If ya do, then this is the game for you if you must choose. If you're apathetic, or you know even a little bit of programming, or want to use the game w/ the MORE POWERFUL (and easier from my understanding) editor, you must obviously choose DS.
Will NWN be full 3d? No
Will NWN have load screens and separate areas and monsters that can't figure out how to follow you when you leave the screen? Yes
Will DS have a live DM to tweak the role-playing aspect of the game and throw in unexpected kinks into the gaming experience? No
Which will have the bigger landscape? DS obviously will have the bigger single area, but when you talk about multiple servers, it's impossible to tell. The possibilities are mind-boggling for both games.
Guys, go to the forums for both games (www.planetdungeonsiege.com and then that other site for NWN), learn as much as possible for each game, and become all-consumed by the games before you choose which to get if you only get one.
And enjoy!