The stuff I actually use:
The one on my person is a Fenix P3D (2-CR123a batteries, 215 lumens).
My headlamp in my daypack is a Princeton Apex Pro(2-CR123a batteries, 130 lumens).
I standardized on CR123a batteries because I order bulk quantities, worked out to $1 / battery shipping inc. for Japanese not cheap Chinese versions.
I have assorted Photons all over the place (key ring, key ring on my daypack, zipper pulls).

Stuff I have around the house but never use:
Maglite (2 D-cell)
Maglite x3 (2 AA)
Petzl Tikka Plus (3 AAA)
Petzl Tikka (3 AAA)