Costa Rica is an awesome country....both sides....however IF you want to see a country that is a little less developed tourist wise go a bit further south to Panama. They are just entering their tourism industry and there are excellent deals to the Royal Decameron and Gamboa resorts.
Decameron is on the Pacific so its tidal ocean, not carribean style calm waters. Very nice and very warm water. Gamboa is inland near Panama City...in the middle of a Rain Forest...great for birds reptiles etc etc. Spectacular view. They have packages where you can stay at each place as part of the same vacation.
Heres my link to Panama Pics c/w Flames in Panama...LOL...
http://community.webshots.com/user/dayel1956
The all inclusive is nice cuz you get your meals/drinks/smokes whatever paid for with no worries...and you can hop on a bus or rent a car at the resort and drive anywhere...safely...for cheaper than here....both in Panama and CR.
I suggest you read Debbies Carribean for reviews on resorts and locations...best on the web for resort and country reviews. I suggest giving in to the wife and doing the resort thang with day trips as needed to outward locations. We went to an all inclusive at the Royal Decameron in off season for less than $1500/flight/resort/everything.
http://www.debbiescaribbeanresortreviews.com/