I like Act II Butter Lovers popcorn.
BTW, I got these microwave popcorn tips from the Boy Scouts during one of my son's popcorn drives:
Always warm up your microwave before making your microwave popcorn. Put a cup of warm tap water in the microwave for a minute or so prior to making your popcorn.
Before putting the microwave popcorn bag into the oven, loosen the popcorn kernels by gently (you don't want to rip the bag) kneading the bag. Spread them out over the area of the bag.
I find that this really helps and makes more of the popcorn pop.
DH has another tip: After the popcorn is popped but before ripping open the bag, turn it upside down and shake out the unpopped kernels from the small hole at the top of the bag where the steam is allowed to escape from. Then you can toss the unpopped kernels and not have them in the bottom of the popcorn bowl.
As you can see, we take our popcorn popping seriously at our house!