No black/ white endings, just shades of grey. Choosing between the lesser of evils. And please no almost-impossible-unless-you've-leveled-up-perfectly final boss.
Tough one, I could name at least 10 I'd want to save, but in the end I'd go for NWN2: Mask of the Betrayer. The story, the partymembers en about every single line of dialogue... it really got to me.