This is the definitive AD&D RPG. The depth of the gaming world they've created here is unbelievable. It's a shame I don't have more time to spend just wandering about finishing all the side quests.
A number of new character classes have been added from the first BG, and while the differences are slight, it's always nice to know they're there when you need 'em.
The addition of a romance portion was cute, albeit a bit corny. I suppose that was included to feed the ego's of the stereotypical AD&D nerds of the world.
I, for one, am a big fan of the new Autopause feature as well. BGII allows you to set a variety of situations where the game will pause for you. This allows the player to customize his/her gaming experience. In my case, it saved me from attempting to guess when each of my characters had completed spellcasting and were awaiting orders.