Wow! My two very most favorite things to do. If you can handle it (the cost), do both.

Captain Andy has a great Napali Coast sunset dinner cruise with unlimited soda, beer, wine or mai tais. If any of you tend to get seasick, take precautions. It can get rough, but sometimes is real calm. You just never know. It is a beautiful trip and you get right up close to the cliffs. It's a catamaran, so the kids (is that what 16DS means? ) can sit up front and get soaked if they're into that! Blue Dolphin offers something similar. I've done a snorkel tour, but the sunset cruise was far better IMHO, just because of the time on the open water and the coast, where you spend a lot of time, is just stunning. Oh, and potentially some great whale and dolphin watching.

Princeville Ranch Adventures for the zipline. The guides are great, the scenery is great. IMHO, skip the zip and dip and just do the zipping. With zip and dip, you get lunch, but it is a royal pain to take off all the gear for lunch and a dip (swim) and then have to put it all back on for one final zip. Take an early morning trip - it can get pretty hot. On the way back, stop at Bubba's (Hanalei) or Ono Char Burgers (Anahola) for lunch!

If I had to choose, I guess it would be the zipline, but if the water is rough, the cruise can be very exciting (not dangerous), just wet and wild.