BushcraftBrainTrust beat me to what I was going to say, except for one thing.
First, I recently received a couple of Quarks, an AA and an AA2. I got the warm tint LED versions and they give really good colour rendition in the field, much better than the usual cool-blue tint LED's. I'm well impressed with them in every way. They can also be had in CR123 models, but note that the warm tint versions are limited supply and will run out soon.
As to the surefire 6P, that's a great idea with the Malkoff dropin as an upgrade. Personally I got the Malkoff flashlight body as well, instead of the surefire. It was cheaper that way as I didn't already have a surefire host.
The dropin I got was the M60W MC-E. Again, that's a warm tint LED and it gives over 400 lumens on high, 15ish on low (with the Malkoff dual mode ring in head). It's a flood light, not a thrower though. It completely lights up everything in front of you, with really good colour rendition. It's definitely my favourite outdoors light. I got the MD2 and MD4 Malkoff bodies so I have a choice of 2x CR123's (or rechargeable RCR123's) in a short body, or 4x CR123's or (best of all) 2x 18650 rechargeable cells in a long body. I can't recommend this combination enough. The ability to use CR123's as well as rechargeables means that I can use rechargeables normally, for cost savings, but keep long-life CR123's in my pack for emergencies if the rechargeables run out.
For dense woods use though, something like the quark, or a light with throw rather than flood, is better because it lets you illuminate things through the trees, without lighting all the trees up in front of you which makes it harder to see deep into the trees.