Concierge.com's insider take:
While the 79 beach and 50 overwater villas got stylish upgrades in 2007, the real stars here are the 21 couples-only spa villas. Designed by leading Thai architect Lek Bunnag in 2005, this resort-within-a-resort is made up of cathedral-ceiling stilt houses of weathered wood with floor-to-ceiling glass walls, plunge-pool-size bathtubs, and a two-table massage room. You can slip straight into the water from your split-level deck to snorkel with vibrant green and violet parrot fish. Experienced dive masters are on hand for eco-friendly excursions (anchorless boats protect delicate marine life), which often include giant-turtle sightings. Afterward, unwind in the overwater spa whose unlit tunnel entrance symbolizes the journey from urban stress to island idyll. Inside, therapists carry out such exotic treatments as an organic pineapple and papaya body scrub in sunny, glass-floored treatment rooms. The best food options are at the wine bar (with 101 cheeses on offer) and the organic Mandhoo spa restaurant. But Ithaa's kitschy all-glass dining room 16 feet underwater gets the most attention. The food is decent, but it's the live fish that make the meal. Be sure to make a reservation.