Not a developer title-wise, but its basically what I spend a lot of my time doing. Programming time at work is basically 50% MATLAB, 30% Perl, 20% C++ with occasional Java or *nix-shell thrown in.
My $0.02 on Win-vs-NIX: I don't think Windows is going away anytime soon, and you can do some really, really cool things with the Windows API. Regardless of your feelings about the Microsoft business strategy, they make some very impressive and very widely-used tools. It pretty much all boils down to your target market: if you're writing for yourself or for a very specific group of users, use whatever OS your hardened, prejudicial soul desires. Larger audiences require greater coding flexibility, nicht?