I use Kernal Seasons popcorn seasoning on my popcorn. I spray the popcorn with butter spray and then put the seasoning on. It comes in a variety of flavors...sweet, cheesy, and hot. We keep several on hand for a nice variety.
Sometimes I will throw a bag of fruit snacks or a small handful of almonds in it to just for a little extra flavor. It's great and prevents boredom!