Well... I'm under the impression that more Germans speak English than do French people... and definitely more countries speak French than German (swaths of Africa and Canada in addition to France itself, for instance)... so if it's your goal to travel, French would be far more useful.
I actually learned more about the English language from French than from Spanish; I've never studied German, though, so I can't provide that perspective. It would be interesting to learn a Germanic language. Then again, German isn't all that pretty-sounding, compared to French. Depends on your tastes, of course, though.
French was very interesting and easy for me after extensive study of the Spanish language. As Sungchul mentioned, the cognates are fun to identify--with the added benefit of more English-French cognates, due to the Norman influence on England way back when.
So... that's what this corner of the internet has to say. But hey, if you're interested in them both, you'll be happy learning either one... and there's nothing stopping you from someday going back and learning the other. There are tons of language schools in Europe where you can take immersion classes and such, and it's great fun.