Sihanoukville
This is a good base from which to explore the tropical islands dotted off Cambodia's west coast. Koh Khtea and Koh Ta Kiev are worth a daytrip, places where you can enjoy some great snorkelling. If you're looking for an overnight stay, head down to Koh Rung, Koh Pos or Bamboo Island. If you don't feel like leaving the mainland, head down to Victory Beach (the backpacker hang out) or Occhenteal Beach (great sand bars and restaurants)