I have been to #1 Panama, #2 Peru, #3 Nicaragua, #4 Spain and #7 Ecuador. I would highly recommend Peru and Spain.

Peru:
I spent about 3 weeks there in total and been to a few places like Mancora beach, Lima and Cuzco. The food there is amazing(you gotta try ceviche) and the culture there is very different to any other parts of the world. The most exciting part is Machu Picchu, one of the seven wonders!

Spain:
Spain is a very big country and every different region has its own specialty. Madrid and Barcelona would be the must visit! If you have a longer time, check out Segovia, Toledo, Valencia, and Sevilla. All cities have a historical town where by there's so many impressive medieval architectures. The food in Spain has more variety like from paella to all kinds of tapas.

Comparing Peru and Spain, Peru would be the cheaper to travel around but safety would be a concern. Nevertheless, it would be a very adventurous journey. Spain is a modern first world country, it's considered one of the cheapest destination in Europe but the cost would be higher than Peru.

I hope you find your destination soon! Update us about your decision and trip! Thank you.