Features I'd like to see are waterproof, single battery (AA, AAA, or CR123), simple (on/off is OK), rugged, and no unnecessary bulk. I have a Fenix LD10 and an LD15, and would be pleased to have either of these in most situations.

The best flashlight is the one I have with me. I may own a totally awesome flashlight that puts out 600 lumens and lights up the world. However, if I found myself always leaving it at home or in my truck, then realistically it wouldn't be with me if I had to stand up right now and sprint out of here.