For what it's worth, here are some of my favorite flashlights in various form-factors:

• 1xAAA: The Preon ReVO was pretty amazing, but unfortunately it isn't made any more. You can't have mine. I can't recommend any of the current-controlled multi-mode 1xAAAs out there because as far as I know none of them come on in lowest mode first (they're either H>M>L or M>L>H, ruining your night vision before you can get to the lowest mode). If you can live with that, the Fenix LD01 is probably my favorite (note that I do not own one). The Thrunite Ti has only two modes, but performs admirably and is cheap enough to stash one everywhere.
• 2xAAA: Preon P2.
• 3xAAA: Hate 'em. If I want something this big I'll go with a 1xCR123A.
• 1xAA: Nitecore SRT3 (truly a 1xCR123A light but has a AA extension tube) or FourSevens QPA, FourSevens Mini MA for honorable mention.
• 2xAA: FourSevens QP2A. Mini M2A for honorable mention.
• 1xCR123A: Nitecore SRT3. It finished the race, held a press conference, showered, took its girlfriend out dancing and brought her home before the next one finished. For me, anyway. I use this flashlight the most out of the collection and it's rarely not in my pocket or in my hand. Second place goes to FourSevens QPL -- which is an amazing light. FourSevens Mini ML for honorable mention.
• 2xCR123A or 1x18650 (head is same diameter as the body): Nitecore SRT5.
• 2xCR123A or 1x18650 (head is larger diameter than the body): Nitecore SRT7.
• headlamp: Fenix Headband, followed by FourSevens Quark Prism in close second place.

I have no affiliation with any of these manufacturers.