Elzetta light mount
http://www.amazon.com/Elzetta-Tactic...ashlight+Mount

+

Surefire G2X Taclight
http://www.amazon.com/Surefire-Dual-...e+g2x+tactical

=

This is the most simple, easiest setup I have ever used. Simple push button momentary switch or twist the cap tight and it will leave the light on.
Best bang for your buck. Solid mount, 200 lumens of surefire light, and right around $100 for the complete setup, I don't think you can go wrong.