I find Finnish intersting for some reason. The fact that no-one really knows for sure where it originated and there aren't really any other languages like it. Except Estonian and some other less known languages.
http://en.wikipedia.org/wiki/Finno-ugric
It seems to me that it Finnish is a language that makes sense and would be easy-ish to learn but someone told me it's quite hard. Who knows.
Language teaching in the UK is pretty terrible. As Hip Priest mentioned, we don't really even learn the 'rules' of English...we just speak it so we know it. Also, we have this awful attitude that people should learn English while we don't bother to learn any other language.
We should all learn Esperanto or something.