Like John and Harry, I use the Moffett light. I used the clamp on, tried desk goose-neck, the magnet tiny goose-neck........finally after 18 years of turning trying all these light variations (along with 4' daylight florescent....6 of them in my shop) the Moffett is a pure pleasure.
It moves in every conceivable direction, push it out of the way, bring it straight down and right into a hollow form, above your head, behind your head, directly over the piece, behind the piece on head-stock side. I probably spent as much, if not more, money trying all the other "cheaper" options.
Ruth