So you have played BG2 then, good.
Yes, there is an IWD2.
http://en.wikipedia.org/wiki/Iwd2
It is similiar to IWD1 in terms of gameplay with a brand new story. It was one of the last titles using the infinity-engine, resulting in a sleeker and more optimized combat and gameplay system. The best condition the engine has been in yet. The story is nice too. I loved both of the Icewind Dales, and played them for many hours back in the day. Multiplayer is also great fun. You could probably find it on ebay now for like $5. Or bargain bins in game stores.
Planescape Torment is supposed to be excellent. The setting is very different (obviously not Forgotten Realms) and may deter some. But the reviews and people on here rave about the storyline and roleplaying elements.
AD&D 2nd and 3rd edition are different rulesets. Basically, the mechanics work differently. Both IWD2 and NWN's use 3rd edition, which is more streamlined and simple. It is quite easy to get a hang of and with time you will grow to like it. Don't let it deter you.