25 Dec 2015 15:20
Depends what kind of game you want to make, and what platforms you want to make it for. If you want to make iTunes or Mac games you will probably need access to a Mac, since you have to eventually compile the final product on a Mac. If you want to make 3D games with fancy graphics, you'll need a much more powerful computer than for making 2D games with cartoon graphics.
We use Windows and Gamemaker Studio to make 2D cartoon games, and for that even pretty weak laptops will work fine. You'll of course see worse performance when loading, saving, or compiling big projects, but it's no big deal. We also have an old Mac Mini since it was the cheapest Apple hardware we could find. We use this to build for iTunes and Mac, though all the programming is done on Windows (Gamemaker is Windows-only).
Some programming environments are more cross-platform, and others are specific to Mac instead of Windows.
So: it just depends on what you're trying to do!