Maui

I think the big island was probably my favourite, but Maui was pretty good too:

• Did part of the legendary drive through the dripping rainforest to Hana, but were slightly unimpressed with the scenery. Also the scariest drive of my life with continuous hairpin bends, one lane bridges and psycho drivers.
  
• Haleakala National Park - more volcano :) Training ground for the Mars lander, we were above the clouds wandering around in the giant craters. Would be cool to do a multi-day walk through the volcano craters there.