Dont know what your looking to spend, but I got one at West Marine for $150 and its a Jensen marine am/fm/cd with housing and 2 speakers. If you just want a radio you can have the one that is in my boat. Its one they had taken out of a automobile and installed. It sounds pretty good and I was able to hear it over my outboard.
Go to Best Buy get the $59.00 am/fm CD MP3 input stereo and a set of the 69.00 Jensen speakers. Mount them in a water case from Boaters world or wherever, it'll last as long as the marine sysems you buy from the marine dealers. 2 or 3 years on the salt water is about all your going to get good use out of one. JMHO.