A bit late, but here I am.
I started couch to 5K in march.
Now I'm running 3 days a week between 5 and 7K
I hope to consistently keep running 3 times a week and be able to run 10K by the end of the year.
Since I mostly run late in the evening, I bought 2 of these : http://www.amazon.co...p/product/B00N1SN7I0
A red one and a blue one. The red one goes on the back, the blue one diagonal on my chest.
They are great, very light (as in not heavy) and provide good enough light.
There are other that are cheaper, but mine have a great build.
And there is no price on security.
It should be able to run 36 hours with 1 charge.