i have a clarion marine head unit mounted up in my electronics box and 2 jbl marine grade 6 1/2 .3 way speakers mounted lox in my helm area..basicly using the hull as a giant speaker box..they are flush mounted in the deadspace under the walkaround deck..sounds awesome!!!! you can hear it clearly for a few hundred feet and when running it is clear and crisp...love having the tunes rocking on the way in and out on those long runs...on the ski boat i have a clarion marine head unit and 4 jbl marine 4way 6x9's mounted in the seat bases and am adding to jbl 10'' subs with a 500watt amp to really give it a kick..mounting them in a fully sealed fiberglassed box up under the bow area...
I have a Fusion IP500 coupled to Bose 101's. Great system. I really like the fact that my ipod lives inside the unit with no cables, hook-ups, etc. If anyone is interested, I also have a pair of Bose 131 flush-mount marine speakers, new in the box, that I'll let go for $150...
It kinda depends on what type of system you are trying to do as to what speakers you will want. If you just want a set of speakers and a radio, I would go with a clarion head unit and a set of Bose speakers. If you want a full on rockin boat, I would go with Clarion head unit, JL audio 10" subs with at least a 500 watt amp for each sub, MB Quart 6x9 3way speakers with at least 250 watt amp for each speaker. Amps I don't really have a preference on but Rockford Fosgate has been good to me and I have tried Lanzars and Autotek with good results and not that high priced.