Wow! German! I had it for 3 years in high school and i still can't say a thing! I'm studying French with Portuguese and for now some Latin and this year i'm applying for Japanese I anted also to study psychology but i decided to go to Cracow, because it's near the mountains.
As for your choices: i think you should pick Japanese (i'd like to know German but this language is not for me) But you shouldn't think only about language. Which of these two countries culture, literature etc. would you like to know better?
Yeah... Well, i didn't have a good teacher and a lot depends on this. Moreover back then i thought that German is a hard, ugly language. And so, when i went to Germany and some nice guy asked me about something (dunno about what, but i think "are you all right" or something like that because i was standing outside girls restroom, dozing off and waiting for a friend) and i just gasped and flashed him with with my intelligence saying "Sorry, i don't speak...... Deutsh." I was so nervous i forgot how is German in English