I'd go to any except for France.
That said, I speak a little bit of German, so I could probably get by okay in a German-speaking country. Switzerland is gorgeous, as is Germany and the Netherlands.
People to People is probably the most expensive program available... how long do you want to go for? Rotary is one of the least expensive (plus you do'nt need to know the language), but there are a lot in the middle range, particualrly if you want to go for a semester or a year. We host students from other countries (so far France, Germany and Spain) for entire academic years. That's the best way to immerse yourself and learn the language; do a year-long exchange, not a tour (which is what P2P offers).
Good luck!