What sort of music
quality do you require. If just good alround quality, I would go for the little box type speakers you can get from your local appliance shop. They usually (and ensure you do get) have plastic cones and are plastic boxes with a plastic or similar grill
. I have found these to be very good on boats. Most of the consumer electronics
like Panasonic, Sony etc have good versions of these. If you want to spend some money
, there are dedicated Marine
versions. And really that is a good rule
of thumb. Pretty much the more you spend, the better the quality. Bose have a very small satilite speaker, but very expensive and you have to have the sub to make it perform. So then you are int0 a system and Bose is expensive. Majestic make a copy of the Bose satilite speaker and it is sold on its own. I haven't heard it, so I don't know what it is like. It is designed to be run on a "car radio" system. Any speaker will run on a "car radio" system, so don't think you can't run a home HiFi speaker.
I can name many if you want inwall/ceiling mounts, but not so many have box speakers. And I think most of the car box speakers sound crap.