I'm the happy owner of a half-dozen Pelican dive lights, and the Super Sabrelight is my preferred mid-size dive light. Rock-solid construction, long runtime, easy-to-find batteries, etc. are all winners, as is the shocking yellow color and ~$30 price tag. I use these on my boat, and occasionally as a dive light.
If you like 'em a little smaller, the Pelican Stealthlight is a nice 4AA pencil-beam light with an external switch. One goes diving with me every time I'm in the water.
Interestingly, I find that the twist-head lights are LESS likely to flood than most switched lights - even switched lights have a removable bezel, PLUS a switch, giving more possible points of failure. Every flooded light I've ever seen flooded at the switch, or was a product of a user trying to turn it on by unscrewing the bezel (another gift to society from the Mini Mag) and opening the light underwater.
Might help us narrow down the field if you shared a bit more about your needs?