A good third language?

Okay, my main two languages are Ruby and C++. Although I've learned Ada out of school and I'm learning Scheme in school now, I don't consider them languages I'm generally GOOD with. So I'm wondering what third language I could learn to balance myself out.

>>14

I ALREADY know the conventions of C that aren't C++. I choose not to use C because it is often less safe than C++, involves more code, and is harder to maintain. As for assembly, although I intend to learn it, I realize it is very limited in what is SHOULD be used for.

>>10

And why scheme over other functional languages?