How can I get the maximum light while avoiding heat from a window?
To reduce heat gain from the sun, you need a window with a good "low e" rating (also called low emissivity). You can get similar results on an existing window by adding a film that reflects IR.

You also want multi-layer windows to block heat transmission (a lower U value is better, it's the inverse measurement of an R value you see on insulation). And finally, you should make sure that the window has good weather stripping to block any drafts, causing a direct heat loss/gain to your home.

Here's an article that describes this in more detail.