To me, it all depends on your future plans. For travel (in a vacuum) I suppose French and Spanish are good. It really depends where you want to travel to, though. Personally, I think studying Chinese is a good idea. Sure, you can only use it in a couple of countries, but one of them is huge and very diverse. It's also a place that isn't so easy to travel in if you don't speak the language (which I would assume isn't particularly true of France). And I say this as someone who has studied the languages of and spent time in both China and France. I also think that, professionally, Chinese would be more valuable.
Having said all that, I'm working on brushing up my French. That's because we're moving to Canada from the US in a few months, and French is way more useful there. To put it another way, we have a 4 year old daughter. If we were staying in the US, we might have her study Chinese or Spanish or German (wife has a connection). In Canada, though, French certainly seems like the way to go. So, again, I think it's tough to recommend anything in a vacuum.
Furthermore, personally, I find it very difficult to study something without a real purpose. At work, I've done various online courses (R, Python, SQL) but if I don't have an application, it's tough to maintain the momentum. So I'd pick which every language you have the most "juice" with, which could be determined by future plans (or just because you like it for some reason).
One last thing on Chinese -- don't be put off by it being "too hard". I've heard that a lot, and I actually find it way easier than French. The pronunciation is different than English, but very consistent (unlike English). If you drill the phonetics at the beginning, your pronunciation will be good forever. And, grammatically, it is WAY simpler than French. Verb conjugation is dead easy (just adding a couple of particles), there's no gender / formality stuff, word order is flexible, etc. I also find reading to be not so hard. And, if you can read and know what words sound like, you can type. All that being said, learning how to write seems very challenging, and I can't write a lick.