I'd say C++. Object oriented programming becomes very useful as you learn more, even though I'm not really at the advanced level.
C has an outdated clumsy syntax and is just boring to use imho. It also doesn't have the new features of C++ like the string library or Classes. It's not OO, it's procedural, which has its limitations.
C is faster though. But I've tried both and C++ is so much better, if a little complicated at times. C++ is also more streamlined, and this makes it easier because things can be done with less code.
If you hadn't guessed already, C++ is the way to go as far as I'm concerned.
Master of common sense. If you don't like it, stop reading.