I think the Aqua Signal (scroll down a bit, they're called Toronto) chart table lights are the dog's whotsits. They dim by using a nifty polarising filter rather than a red shade. Not cheap.
Worst things are those bendy car ones. Complete rubbish as the area of illumination is usually far too small. You have to keep on adjusting the poxy things.
-------------------- "Procrastinate now! Don't put it off"