We have a 12v lighting system with little halogen spot lights dotted around the boat and they are great and give off plenty of light, all of the bulbs are 20 watt and are bright. Just over he bed we have a cupboard and this is directly over where our heads are. There are two reading lights...both 20 watt!!! that nearly burn your eyes out. I popped to Tesco yesterday and found they do these bulbs and I found some 10watt....lets hope our sight is saved ;-)
Oh yeah and they are a heck of a lot cheaper than Midland Chandlers (which isn't hard)