My only study abroad regret is that I didn't stay longer. IF I could do it all over I would've gone away for the full year. With a semester, just as you're beginning to get used to things, you have to leave.
There is absolutely no reason not to study abroad. The benefits are endless.
As far as programs go I personally recommend the School for International Training (
www.sit.edu). Their programs focus on cultural immersion and focused subject matter -- each one of their programs has a theme. For example, my program (in the Netherlands) was "International Perspectives on Sexuality and Gender". There are public health, social justice, education, environmental studies, multicultural studies, gender studies, arts programs, and even special themes like "State Building and Human Rights," "Migration Studies," "Pacific Islands Studies," etc. Each program (with the exception of a few) requires each student to do an independent study project that takes up the last month of the program. It sounds daunting but it is honestly the most rewarding part of the program and the part I learned the most from. They also have really good language training and place you in homestays with local families, which is awesome. Please, if your school accepts credit, check it out. It's a different experience from what most American study abroad students get. They also have intensive language learning programs in Morocco (Arabic), Spain, and France that don't have any prerequisites.
Host families facilitate language learning and cultural immersion. When your host family is sitting around at the table conversing in Dutch all day, you learn it a lot more quickly. At the end of my semester (before which I had never learned a lick of Dutch) I could follow a simple conversation and watch a movie subtitled in Dutch. The only other option I think might be cool is living in a dorm with other international students or mostly students from the host country. I wouldn't want to live an apartment alone or with other American students; I can do that at home.
As for language, I was in the same boat. I had taken French for several years, and a French-speaking country was my first choice (I actually applied for a program in Switzerland, but due to a mishap with a teacher recommendation the program closed before I got all my materials in) but in the end it didn't really matter to me. The international experience was great no matter what language I learned.
Oh, and don't ask yourself if you can do it. You can. You'll be kicking your own ass the first couple of weeks, but after you get over that hard spot the beauty of the experience will hit you. I'm not even kidding.