WhatTheFAQ: This has been a long drawn debate for years. To be quite honest, I don't think it matters which one you start with, as long as you learn the other. Personally, I use C more than C++, but C++ is really alot easier to use for GUI apps. I would recommend looking at both, and see which one you like more.
Yeah, and the mere knowledge of just C or C++ won't get you coding a PS2 GS plugin