You know, those lights you see in the garden aisle - the ones with a solar cell on top and a tiny LED that you can put anywhere? Well they seem to be popular items with boaters - here at Shilshole anyway.
Perhaps they appeal because they are "green", or because the light they produce is free, or maybe because they need no wiring. But most of the boats out here on the end of G dock have several of them.
On Eolian, we like them because they provide an eye-level alternative to the "official" anchor light (on the top of the mast, 65' above the water). The official light is good for drawing attention to an anchored boat from far away, but for, say, a small fishing boat threading its way thru the anchorage, they are so far off the water as to be irrelevant. So we do what we can to make Eolian more visible from close up, near water level. We have several of these "driveway marker" lights - they are designed to be driven over, and are therefore weather tight and very sturdy.
Some lights are for welcoming, and others are just for whimsy.
Doug and Ruth on Angelique even have these party tiki solar lights - they produce a flickering yellow-orange light!