Actually Vista includes a screen capture tool that can capture windows, rectangles, the whole screen, even a lasso. (Admittedly another example of Microsoft stealing markets from third-party developers.)
But sometimes I do need the regular print screen key. (To capture the start menu, or in full screen games, for example.)
Input Remapper seems interesting; does it work in games?
I personally like the registry change best. It's more complicated, but it is part of the normal Windows keyboard driver so there are no additional processes running, no additional layers between my keyboard and my games, and no compatibility issues.