As of now, the only item that carries over that allow you to continue on with it in a quest-like manner are the gold pantaloons. I'd like to see one or two more items that one can do this with. For example...
-The autograph from Larry, Darryl, and Darryl could open up a neat quest if given to the right person.
-Marek's antidote could be saved and given to someone in BG2 who had also been poisoned in the same manner.
-One could carry Bala's axe into BG2 and run into someone who is a direct descendant of Bala and recognizes the axe.
-Vampire's Revenge could be used! You already have to go out of your way to not complete another quest in order to obtain the hidden sword. What if it could be carried into BG2 and given to a warrior who has been searching for that exact blade for some purpose that involves a new quest?
Having two or three items from BG1 that can open up quests in BG2 allow the games to feel a bit more connected, it gives a small bonus to those who have gone through BG1 before playing through BG2, and it is very exciting!