I lived aboard for over 20 years and still miss it. The way I would rank the conviences would be: 1. a seperate shower stall with the hot water
2. a microwave 3. a TV with cable or sat connection.....all of which set up so that you can undo the dock lines and go for a sail on a moments notice.
I went a couple of years just using block ice in the frig rather than converting to the DC system. It was a well insulated box and the 20 lb block would last about a week even in the heat of the Cheaspeake Bay summers.