Scheme, because of this book: http://mitpress.mit.edu/sicp/ Why argue with the MIT folks? Followed immediately by: C, Javascript, and a scripting language (Ruby or Python are good choices). You've also got to work Java in there somewhere, just so you know where people are coming from. It could come first, or last, depending on your tastes. If you love Windows technologies you can probably substitute C# for one of tho…
Why argue with the MIT folks? Because even MIT changed its intro programming class's language from Scheme to Python.
That said, I would still have liked to learn Scheme or a Lisp as a first language. It's a tiny language at its foundations and allows you to express many different computer science concepts with little effort. Also, it's much, much easier to write a Scheme interpreter in Scheme than a Python interpreter in Python.