xabi - south Lantau does have easy access to some of the best outdoor activities in HK, though that doesn't make them 'world class'. However, there are mountain bike trails on Chi Ma Wan, not far from Pui O, and some good hillwalking; paragliders often use launch sites on the slopes of Sunset Peak when the wind's in the right direction, and try to land on the beach at Cheung Sha, where there is at least one good restaurant. Surfing? You might be lucky...
Commuting is not too bad, despite the restriction on private car useage - there are lots of buses, and it only takes about 30 minutes from Cheung Sha to Tung Chung, near the airport. Taxis, though sometimes difficult to get hold of at peak times, are reasonable too.
Mark Six is right about the village houses. If you're lucky, you'll get a nice roof-top with good neighbours. However, if they, or their dogs, are not domesticated, you'll certainly need lots of earplugs. Expect to pay significantly more than $5500 for the top-floor with roof top flats, though.
Good luck.