I am just changing my deck light fitting - ripped the old one out and bought the new... now just need to rewire
I have stayed ewith the Halogen bulbs because the deck lights are only on for a few minutes when so foredeck problem occurs. I normally have NO lights on at all, and NO torches when I do deck-work because you get used to it and its better to not need lights
I just did a circumnavigation so its over a bit of experience.
If its a long offshore race boat you need lots of deck lights for spinnaker changes etc.
If you want deck lights to look pretty at anchor then you need LED. The do not work as well as Halogen but boy they don't draw no juice
By the way, some folks (me!) have the combined steaming light /deck light. The steaming light, obviously, can be halogen too as its only on when the engine is on!