JamesK once bubbled...
Yes, I can honestly recommend a HID to the once a year diver. Even a cannister type. Think about it, you spend $400+ on a BC, anywhere from $250-$700 on a regulator, $120+ on fins, etc etc, why not $450-$650 on a good HID. You can purchase a Pro4 or Pro3 Halcyon 10watt HID for under $600. You can purchase a DR 10watt with wreck 1 cannister and MR11 head for under $600. You can purchase a Rennacker light 10watt HID for under $500. Why not get the best equipment for the job? If you are going to be diving any kind of low vis, it will make a LOT of difference. IF you are strictly doing high vis and just need a light for night dives, and peeking in holes, then no an HID is not necassary.