I installed (2) 10", (4) 8" & (4) 6 1/2" Memphis Marine speakers last year VERY HAPPY with the results.
Steve

ive had really good luck with polks in my boat

I am assuming the 2 10" are subs. You run 3 amps for all that?

You could easily run 2 amps for that. One Mono amp for the subs and a decent powered 4 channel @ 2 ohms for the 8 speakers.

Has anyone heard the JL Audio Marine speakers? there are a couple of boats around here that really sound good , sound quality was amazing to me . been thinkin about buying some of those .

They're very pricey......

Seriously, checkout the Wet Sounds stuff. The XS-650 that they make is louder and cleaner than the JL's.

Wet Sounds does make some nice speakers. They're big down here in Texas and you see them all over the wakeboard boats. Wet Sounds puts on a stereo competition each year at one of our poker runs and some of their boats are crazy sounding!

I knew the JLs sounded great in both of the boats that i heard them in , but when i read this whole post i was very suprised that i didnt see them mentioned . So i was kind of leary mentioning them thinking i would have to put the flame suit on. But then went and checked on the pricing of them , and was like damn these things are pricey..... .
I will say this , One of the boats that i heard was just this weekend at the island we tied up at , and i walked over and was like wow what is that guy running and how many speakers , to my suprise it was just two of the 6.5 " and one small amp. It was crystal clear....

Yeah, the JL's come stock on Mastercraft's now, and they do sound good......

I have Memphis as well that I just bought, (2) 8" 2 way's, (2) 6x9's and a single 10" sub running off a JL 4 channel (300/4) amp. I'm very pleased with the sound quality and the punch of it. Doesn't go real low, but it is PERFECT for the rock I listen to. Pricing is pretty reasonable for a reliable brand name.