Well, after much debate, and a lot of help from you guys on here, I finally made my decision.
I went with the Solarforce L2 because it was only $12 and a lot of people gave it pretty good reviews considering for how cheap they are. Its customizable, unlike others, and it is exactly 1 inch round which will help mounting in the Elzetta mount. I know there are newer versions out there, but I wanted the rear clicker to be fully exposed so I can use the gun sling bracket to activate the flashlight. The new L2P version has an inclosed tail cap which means you can't push the button with the sling bracket, so I bought a little older version, but works better for me.
http://www.lighthound.com/thumbnail.asp?file=assets/images/soll2bk11.jpg&maxx=600&maxy=0
I am putting the Solar Force XM-L T6 Drop-In in the host. It seems to be one of the newest drop-ins. It was only 15 bucks, puts out around 500-550 lumens and will definitely fit my host. I don't know much about the drop-ins and hosts so I figured even I couldn't screw this up.
http://www.solarforce.hk/products/201208121249423.jpg
I also bought the UltraFire 18650 3000mAh 3.7V Rechargeable Li-Ion Battery (Pair) + Charger Combo off of Amazon. 12 bucks seemed like a good deal.
http://ecx.images-amazon.com/images/I/81VHDIjkxYL._SY300_.jpg
I got by with a pretty cheap build compared to the other lights I have seen; about 40 bucks. I should have a pretty darn bright light when I get it all put together, that will be customizable to meet my needs without breaking the bank.
Thanks again for everyone's help. I still want to get a light that has been torture tested and guaranteed to withstand anything, but I can't justify spending that much just yet.
I'll post a few pictures when I get everything assembled!