Steve and I just booked our tickets to Costa Rica to celebrate 5 years together in March.  We're hoping to mix a little adventure and little bit of lying on a beach doing nothing.  We're flying into the Liberia airport (it was significantly cheaper than San Jose) and planning on renting a car.  I've heard that Monteverde is incredible as is the Arenal Volcano National Park.  I'd also like to see some cool flora and fauna. Any recommendations for things to do, places to go and food to eat?