My go-to is a Surefire G2. Takes 2x 123 batteries, of which I bought a case of and got a great price. I switched to this from a Pelican where the tailcap button wouldn't lock on anymore. The G2 has been through some very rough environments, 6-7 days/week for months at a stretch, and never failed me. Great battery life even with the high-output head (I think it's 120 Lumens?). Although if you're fire fighting, you might ask other fire fighters.. regarding materials, battery type, heat, and spark suppression. The last thing you want is it getting hot and leaking or exploding.
I also have two Surefire 9Ps around, which are great, but I've found they slowly drain the batteries over time (many months), even when you back the cap out all the way. Was going to contact Surefire about that issue.
Beyond that I have two MiniMags, one standard incandescent and one with the 3-LED head and push-button tailcap. They take two AAs and are solid.
Then a bunch of "other." A two D-cell incandescent, a cheap 5-LED thing, maybe another Maglite somewhere.
Just my experience. I know Fenix and a lot of the others have gotten really popular in the last few years, but I haven't spent the money for any of that. Would rather spend it on ammo and training than more kit.