Your choice of second language does not signal that you're "educated". How well you know that second language is what signals your education.
You could speak Spanish flawlessly and fluently and be come off as downright impressive and erudite. Or you could speak French filled with "um... er... uh..." and come off looking rather foolish.
But what would be the *best* sign that you're an "educated person"? Well, an educated person would make a wise decision, of course! A wise person would choose to learn the additional languages that he or she came into contact with.
In other words, if you're likely to travel to France, or parts of Canada, learn French. Otherwise, don't be a poser and learn a language you'll never use. If you're likely to travel to Japan a lot, learn Japanese. If you live in the southern United States, you should be beaten for even asking this question when Spanish is so obvious. If you live near a Russian neighborhood, learn Russian. If you're in Chicago, learn Polish. If half of the people you work with are Chinese, learn Mandarin. If you're in the military, learn Arabic.
Don't try to choose a language to make yourself look smart. That will only backfire, and make you look foolish.