Surefire: Because they are simple. Not saying the design is weak, or not well thought out. SF have been around a long time and have tweaked most of their designs and learned from a huge amount of experience, where the weak parts of a light are. But I say simple, for example the 6P, hardly any moving parts, nothing that can really break, everything can easily be replaced. Moderately strong. There are lights in the line up which are strong, but light, so wouldn't break from a fairly high drop.
HDS: Bulletproof design, a bit more complex with the electronics, but take the Ra Twisty... I don't think I could kill one even if I tried really hard! solid little lights.
and my current workshop light, because of supposed toughness
Innova X05: Its only 5x5mm LED's but a tailcap like a surefire, probably direct drive so no hardcore electronic wizardry, and can supposedly take a tank rolling over it or some such nonsense... I like it because for the price, I can have a few backups.
Oh yeah, and if you want super rugged, but don't care for brightness that much, a water tight keychain light. Seriously, would survive a fall from an airplane because they are so light for their size
