As this site's loudest C++ programmer, I would suggest that you start with C. It gives you an appreciation for any higher level programming languages you may learn down the road, forces you to focus on the intricacies of your operating system, and is really good for disciplining a programmer.
Yeah, C++ is great, but to start with C++ makes no sense because C++ was made (in part) as a response to C. It would make more sense for you to start with C so that you have a solid foundation of system internals and what really goes on under the hood before starting C++, which adds abstraction and more programming paradigms.
Oh, and C and C++ are not the same. If you write C code and compile it with a C++ compiler, yes, it may compile; but you will have just written the most garbage C++ of your career. Good C is not good C++ and vice versa. Don't let anyone tell you different! The creator of C++ himself (Bjarne Stroustrup) said so himself; One of the most prolific C programmers, Linus Torvalds, abhors C++.
While I believe that C++ would make for better malware (frameworks like Qt will make multiplatform support a bit easier), having that C discipline will make you a more elegant programmer.
@0x00pf's opinion would also be useful here.
I don't know anything about C#, so as any computer person would say, "I hate it."