never played either back in the day, kind of regret it so i found this awesome website back when gaming was great and am looking for a great in-depth rpg game i can playing multi with a friend.
So what game is better BG2 or NWN or some other rpg on this site i don't know about :P
any suggestions is welcome
Personally I think NWN is by far the better choice, and not just for MP. Yes, I know I'm in the minority folks and I'm not trying to start a flame war, but for my money NWN was a lot more engaging and entertaining.
I liked BG II but what most people seem to like (i.e. the party banter/interactions) wore on me quickly and I'd personally like to think that the writer who wrote the dialogue for Minsc and the voice actor who portrayed him are both suffering some sort of terrible karmic retribution for what they did to my nerves. IN NWN you can choose henchmen but are not obligated to do so. Even if you do, they are talkative at times but don't natter on incessantly and don't bicker with you.
Having said that, BGII is definitely worth playing. It's combat system is good though if you are a PnP fan it's worth noting that it uses the 2nd edition rules like most of the Infinity engine games, whereas NWN uses a psuedo 3.0 edition of the D&D rules.
Also, and again I'm in the minority here but I felt BGII gave an "illusion" of an open world rather than actually delivering one. That said NWN does the same thing. You can choose to explore areas when you want and do or not do sidequests in any order you choose but you can forget packing up and just going to Waterdeep instead of dealing with the quests presented, you are stuck with them.
Graphically, NWN is leaps and bounds ahead, as it should be, being a much more recent game. Also there are some mods, like CEP, that raccthet it up a few more notches. There is the obvious difference of a 3D NWN vs. a 2D BGII, however BGII graphics have aged well and look nice, they just don't look as nice as NWN IMHO.
Without knowing more about what you like in a game that's about the best way I can break it down as to why I think NWN wins. Realistically GOG has an RPG to appeal to just about any type of RPG gamer once you know what style of game you like.