If you're using 18650 batteries already, you should certainly get yourself a good flashlight. If you've never had a decent LED flashlight, you'll be shocked at how much better they work than, oh, say your big 3 D-cell maglite that you think is a good flashlight.
Even the little ones that use 3 triple-A batteries will put a maglite to shame.
I have a few 18650 flashlights that put out about 500 to 900 lumens. By comparison, the 3 D-cell maglite puts out about 77 lumens. While the 18650 lights are impressive, they're not all that useful other than bragging rights (like I just did above

). My go-to lights are single CR123A lights. I use LiFePo4 rechargeables because they can be recharged 4x more than LiIon batteries and they're compact. In fact, I have 4 of them, EagleTac D25C Clicky, Sunwayman V10R, Olight S10 and T10. They all put out about 230 lumens and step down to lesser lumens but longer runtime. I find that medium on all of them (about 100 lumens) is more than enough for 98% of my needs.
Lately, the Olight S10 has been the one I grab most often. (stock photo I found online, not mine)