We stayed at the Hyatt at Ka'anapali. We loved the area. The Hyatt was significantly cheaper than Aulani and it gets great reviews. Our room was outdated and nothing special, but we had an ocean view and when I opened the drapes it was gorgeous. The lobby is beautiful and they have parrots, penguins, flamingo and cockatoos there which DD loved. The have an area with some shops attached and a Luau on premises (we did not do that as we felt we had enough of that with the Star Hui and the Polynesian Cultural Center while we were staying at Aulani and wanted to do other things) The pool area is nice (has a swim up bar), there is a good stretch of beach to walk down. Breakfast was included with our stay and it was a large buffet in a really pretty restaurant area. We chose the Hyatt over the Grand Wailea for the area. The Grand has nicer rooms, but it is much more expensive, and we weren't in Hawaii to be inside the room. We would stay at the Hyatt again.
Our absolute favorite thing we did in Maui was drive the Road to Hana. It was absolutely beautiful. You want to buy a CD guide (there are a couple of different ones that are good), as that tells you the mile markers to stop and look at things, some of which you don't see from the road, or which take a short drive from the main road. You should get an early start for that one because there are so many places to see and explore and you will run out of time, and you can stop in Paia and grab a sack lunch from one of the many places that sell them to people starting the drive (you won't necessarily find food on the drive when you are ready for lunch- there are just a couple of places here and there). It is an all day experience and takes you to gardens, waterfalls, beautiful ocean views etc. There is a place along the way called the Garden of Eden that costs to get in, and we were glad we paid because it was beautiful. We did see some tour buses along the way, but I would much prefer to drive our own car so we could stop wherever we wanted and stay as long or short at each location as we wanted. My DD and DH loved the Haleakala Crater. You basically drive up to an altitude of over 10,000 feet and then you can hike around. For me, that drive up was scary and I got altitude sickness from hiking at the top. It makes for great pictures though and it is something to see. The terrain at the top made DD feel like she was on a Star Wars planet. For me, the Road to Hana was much more my style and speed!