I have a Magicshine and a P7 flashlight. I bought the Magicshine first, because I needed more than 45 minutes runtime. Well, now that I have both, if I were to do it again I'd just get the flashlight. It turns out that I definitely do not need that much light; the flashlight on medium (about 250 to 300 lumens I'd guess, given my prior experience with the Dinotte 200L) puts out plenty of light for me, and in that mode I get over 2 hours of runtime.

The flashlight is self contained, simple and waterproof, and I can grab it off the bike and use it handheld. Batteries for it are cheap; a few bucks each.