Costa Rica is a beautiful paradise with friendly monkeys and rough west-coast waves (lost my snorkeling gear to one particularly nasty wave!). We stayed at a hotel on the edge of the Manuel Antonio National Park, which was divine. We also stayed at a Marriott outside of San Jose on a coffee farm. Magnificent. Note to tourists: take taxis, don't rent a car. The roads are in terrible condition and robbers abound. If you're a SCUBA diver, be sure to check out the rainy season dates - SCUBA tours do not happen during rainy season. One day I WILL return to Costa Rica and take the canopy tour. That is my only regret!
Costa Rica is great. Try rafting on the Reventation River. The Canopy tour is an experience. Try to choose a canopy tour company that has a good reputation. I have seen some canopy tours that aren't challenging at all. For travelling, throughout the country, I recommend flying Sansa or Travelair. The roads aren't in great shape and the air companies connect with most destinations in Costa Rica.
PS- Travelair is now called Nature Air. Nature Air can do connections to Nicaragua and Panama also.
Another vote for Costa Rica. Friendly people, loads of exciting activites and some of the most beautiful beaches I've ever seen. (Mal Pais)