Re: Looking for an OS.
I guess it would depend on how you plan on obtaining this core knowledge. If you are looking into a formal college education and you have the money (or your parents have the money) to pay for it, then Windows is the way to go whether it be XP, 7 or whatever. If you are trying to do this on the cheap, go with some form of Linux so that you may take advantage of the whole Open Source community thing. Plus you can get free open source compilers if you go the Linux route, which is something Microsoft could never bring themselves to do (offer anything for free, that is).
But I'm trying, Ringo. I'm trying real hard... to be the Shepherd.