I really like lights that run AA's - you can get rechargable versions (Nickel Metal Hydride like Tenergy or Eneloop) or Lithium that have a 10-year shelf-life.
You can get ordinary AA's anywhere as well - not so w/ CR123's or 18650's
My two favorites are the Fenix LD12 S (small pocket sized 120 Lumens around 50 bucks) and the Fenix LD41(normal size 500+ lumens around $70) ...run your LD41 at the 80 lumens (more power than a normal Mag Light) power setting, and it will last 20 hours. Fenix has good build quality and they are water proof, IPX-8.
For normal use, 80 - 100 lumens is plenty.