I need some help. I can put either a CrimsonTrace laser or a Surefire light on my .40 Cal Glock model 22. I plan to use it for home defense, shooting for fun at pistol ranges, and some tactical competitions. Any advice would be welcome...What would you go with, the laser or the light?

Why not get an Insight M6, it has both a light and a laser.  The laser would help if you get into a position where you can't use the irons properly.  The light will most likely be a more useful general purpose tool.  Both take training and practice to use properly, but the laser will take more time and practice to master.  Both are good tools to have.  

Umm why not both? www.insightlights.com/prod_m6.htm offers a flashlight/laser combo. So you can have both if you want.

I havent had any experience with either on a firearm but for home defense it would be my opinion to go with the light if you had to choose between them. You want to make sure that shadow in the hallway isnt your kid coming in late from a latenight party. Also a good light like Surefire is quite blinding when being shined in the eyes of an intruder. The only thing with weapon mounted lights is your going to be flashing your muzzle where you point the light. And if you dont use proper light control it can give you away. Up to you.