I tried this recipe from the Sisters' Cafe for white chocolate popcorn. It's delicious! You should definitely make it when you have lots of people to share it with though.
I've also made it into a peanut-y version by adding peanut butter chips and peanut m&ms along w/the usual chocolate chips.
Toffee White Chocolate Popcorn
2 bags light microwave popcorn
1 bag white chocolate chips
1/2 c. chocolate chips
chopped Heath candy bar (I used 2 bars)
Pop popcorn, then remove unpopped kernels. Melt white chocolate chips in microwave (1 minute on high, stir, then 30 more seconds if needed until smooth). Pour white chocolate over popcorn and stir until well covered. Sprinkle chocolate chips and Heath bar over popcorn. Spread onto cookie sheet to dry.