I prefer a simple AAA flashlight with a simple on-off mechanism, such as twist on/twist off. I currently have the Fenix E05 on my keychain and it works fine for me. Previously, I had a Fenix L0P which was similar and worked fine as well.

I appreciate having a light that's more powerful than cheap coin-size lights. It comes in handy every once in a while (at night mostly).

The only flashlight I ever got myself to EDC along with my daily house keys and work cabinet key, was a Fenix AAA-type flashlight. Along with a Leatherman PS4.