Dinner with my boyfriend's parents... What should I take?

Don't take food - they might see that as a bit of an insult. If it's going to be very sophisticated then they will have already planned the meal properly and might take it the wrong way if you show up with an appetizer, like "I didn't think you'd have planned it, so I brought my own" !! Wine or a bunch of flowers are the typical things to take, and so I think you'd be better off taking nothing than something strange!