Just wanted to thank all those that have contributed to this thread. The wife and I just spent a week in Maui. Here's my contribution:
Sunrise at Haleakala - Glad we did it but wouldn't ever do it again. We did it the first day there (Saturday), left Ka'anapali at 3:15 AM which got us there with about 15 minutes to spare. The parking spots filled to capacity so folks just started parking in the empty space jamming the parking lot. Some of those blocking the exit pathway took their sweet time getting back to the car so leaving the area was a test of patience. The actual sunrise was spectacular and yes it's cold up there...VERY cold. Make sure to dress accordingly and bring gloves. My hands were numb after taking pictures for about 10 minutes.
Road To Hana - We rented a 4 door Jeep with a hard top and it was perfect for the two of us. The top over the driver and passenger easily popped off and stowed in the rear. Being the driver I really appreciated the open top as I was able to get some amazing views without taking my eyes off the road for too long. I would suggest that you and the passenger have a good idea of what stops you want to make before heading out for this trip. We had the book mentioned in this thread and it was great, but the wife didn't spend much time with it so it was difficult for me to remember all the stops I wanted to make. I drove right past several of them without knowing until I saw the next mile marker. We ate lunch before Hana where there was a "jungle shopping center" on the ocean side of the road. It had a coffee shop, a few folks selling crafts and 2 or 3 food options. I had the pork taco and it was super tasty. On Google Maps the location is labeled "Terry the Weaver". I really enjoyed the drive on the back side of Hana. Glad we had the Jeep for that section as it gets pretty bumpy in spots.
Golf - I splurged on a package at Kapalua that was a 3 hours lesson in the morning, lunch and your choice of a round at the Plantation or Bay course. The Bay course just had the greens punched so I went with the Plantation course. This is the one that the PGA kicks off their season with in January. It was by far and away the best golf experience of my life. The package included rental clubs which were top notch (Titleist 913 woods, AP2 irons and a Cameron putter). The course was pretty difficult and having not played it before there were several "hit and hope" shots due to the elevation changes. The greens were immaculate, fast but fair. The Bay course is supposed to be quite a bit easier, but I don't think it offers the views that the Plantation course does. If you're looking to play while on Maui, I would highly recommend splurging on this package. The lesson was great, lunch at The Plantation House gave me a view of how the 1% of the 1% must live and the course was just phenomenal.
Helicopter Tour - We did the West Maui and Molokai tour with Blue Hawaiian. It was about a 45 minute flight. The wife and I both really enjoyed it. Absolutely amazing to see some of the islands that you can only get to by helicopter. After touching down at the heliport you can by a DVD of your trip for $25.
Food -
Mama's Fish House - Outstanding, pricy but totally worth it. Make sure to call when you're booking a reservation as the online options were terrible (before 5:30 or after 8:30). Had no problem getting a sunset reservation when we called.
Flatbread - A+ pizza
Maui Brewing Brewpub - Great beer selection, surprisingly good food at a good price. Beer battered deep fried brie served with a caramelized pineapple sauce...holy geez that was good.
Ululani's Shave Ice - Awesome. Make sure to get some ice cream on the bottom.
Overall it was a fantastic trip. Can't wait to go back. If you're at all on the fence about going to Maui just do it. Thanks again to all the posters on this thread.