In reply to The Lemming:
The Fenix LD41 is a similar size to the frogman, also runs off 4 AA batteries, but is not waterproof. However, it is over four times brighter, and similarly priced. Don't have one myself, but I have a couple of Fenix torches, and I rate them highly.
If you go down the rechargeable/lithium battery route then things can get very silly