In the year of the eco-initiative, many of our 2007 top 50 resorts are taking energy savings way beyond towel-reuse programs.The Fairmont Kea Lani, Maui, turns leftover cooking oil into biodiesel, and Disney's BoardWalk, a Florida-certified Green Lodge, composts food waste. If you're concerned about a hotel's practices and policies, ask before you book. Have they installed low-flow water systems? Are they using gray water in the garden and on the golf course? Cleaning chemical-free? Even if the answer is no, you'll help get them thinking.