Installing Outdoor Motion Detector Light

I'd like to install motion a detector light in front of my garage so when i get home late at night the light will turn on.  What are my options?  What should I avoid? 

The Money Pit Answer

A motion-activated security light sounds like a great choice for you.  Higher-quality motion-activated lights can be aimed with good accuracy so they don't go off when cars drive by - they're only activated by people.  They're handy for security purposes, sure, but also just very convenient when you're carrying bags inside and fumbling for keys in the dark!