In March, 2008 we toured around Costa Rica. In short, everyone should visit Costa Rica. It is a beautiful country with jungles and beaches, delicious food, fun and peaceful people, and it's not expensive. We used a tour company (I usually plan everything, but this was a very involved trip) that worked out very well. They were/are www.vacationscostarica.com. A driver in a private van took us from place to place, making for a much less stressful trip.
We started in the Arenal Volcano area, staying at The Lost Iguana. The location was very cool, overlooking the active volcano. There were large, comfortable rooms with patios and a nice pool area. You are essentially in the jungle, so the sights and sounds were great. The food was just average, and stopping at local spots during the trip was the way to go. It is a good place to go on all types of excursions, all of which will pick you up at the hotel so you don't need a car. We hiked to the Volcano, visited Hot Springs (Tabacon, but it was very crowded and too touristy. Try another hot spring if you go) and walked the hanging bridges tour, which was surprisingly cool. We also went on a canyoning and rappeling trip, along with some white water rafting. All of this was real fun, with attentive professionals keeping us safe the whole time.
Then, we were driven on an 8+ hour drive to the Pacific Coast. The hotel was one of our favorites and it is called the Arenas Del Mar. Beatiful rooms coupled with views, beaches and again, nice people, made for a very enjoyable stay. The only issue, and this is important, is that during our stay in March, there is an annual migration of crabs. The place was over-run, literally. They were all over the rooms, the walkways, the outside restaurant. I had to take my wife to dinner on my back, seriously, because she was very freaked out (as was I). But, it got less and less as our stay progressed and now it makes for a good story. But, if you go in March, this could happen to you so be prepared. We did a canopy tour from the hotel, as well as a hike through Manuel Antonio National Park...monkeys, iguanas, sloths, etc. And, the beach is wide and powdery, with a warm, inviting ocean.
Lastly, we stayed at a place not too far from San Jose (the capital, where the airport is) called the Peace Lodge. While it was fun and the room very unique (waterfall showers, jacuzzi on the patio), it was a bit touristy and would have been OK as a day trip. But, we hiked the waterfall trail and that was very cool.
Costa Rica is a trip for anyone, whether a couple or a family. Plenty to do and all types of settings to enjoy.