Personally I think lithium batteries are a good thing and more specifically I really like the 18650 format. In fact, I've standardized on the 18650 format with an HDS Rotary for EDC, Zebralights for headlamps and inexpensive Solarforce lights with P60 format LED dropins for the cars, drawers and kits.

H600w Mk II 18650 XM-L2 Headlamp Neutral White
http://www.amazon.com/gp/product/B00F8J71LE

Solarforce L2P HAIII Forward Clicky flashlight Body Version 2015
http://www.solarforceflashlight-sales.com/product_detail.php?t=FB&s=7&id=354

Solarforce 320Lms XPG Cree Led (Orange Peel Reflector) Bulb
http://www.solarforceflashlight-sales.com/product_detail.php?t=RB&s=29&id=212

There are safer chemistry 18650 options these days like these:

Panasonic NCR18650PF 3.6V "2900mAh" Rechargeable Li-Ion Batteries (2-Pack) https://www.amazon.com/dp/B00F58URPK

Also make sure you get a high quality charger like:

XTAR VP2 Independent 2-Channel Battery Charger
https://www.amazon.com/dp/B00K9T265Y

Yes, respect lithium batteries in general. Don't buy questionable lights, batteries and chargers*. However lithium powered lights enjoy almost no self discharge for long shelf life, power devices for a long time, rarely corrode in a light and provide fuss free charging and operation.

Rechargables mean not worrying what to do when your batteries are half charged -- just throw in a fresh battery and put the old one on the charger.

Also note many of the most risk associated with litium ion cells can be avoided by avoiding multi-cell lights and using good quality chargers with independent charging banks (such as the VP2).

-john


* Admittedly, the Solarforce drop-in P60 "bulbs" may not be super-premium, but they seem to be good enough, at least when it comes to the lower power units like the XPG lights.