Ever wish you had a separate stereo system in the cabin? Here's a cheap way to do it: Buy a Pyle CD receiver for about
$130 (check pricegrabber.com). It comes with a great backlit LCD wired remote, which you can run up to the v-berth. Mount the stereo in the din slot where your current stereo is, that one you can hide in a cabinet or mount somewhere in a SeaHoss $20 mounting bracket.
Pyle also has a cheap 1000 watt 4 channel amplifier, if you want a little more horsepower. I put the 2 Kenwood speakers from the cabin into the v-berth and run them directly off the front channels of the Pyle. I replaced those two speakers with Kicker KM60s and added two more. They were $60 from Crutchfield and the second pair was $30. The four speakers in the "salon" run off the 4 channel amp, two channels coming from each of the rear RCA outputs. I like to wire them criss-cross, so you're always near the sterophonic center. For about $14 you can get a Dual MP3 input to hook up to the Aux input and play songs off your ipod all night.
The main system my cockpit is a Clarion CMD4 (about $230 from Etronics.com, the backlit LCD remote is $114). Its by far the best unit for the money, the remote is very user friendly. When using separate amps, its ALWAYS best to get a head unit with 3 sets of RCA line level outputs, AKA preamp outputs. Sometimes they're referred to as six channel RCA outputs. It gives you separate low level outputs for the front, the rear and the subs, giving you by far the best performance from your system. The cockpit speakers, six Kicker KM60s and 3 Kicker 10" subs are run off two JL Audio amps, a 300/4 for the 6-1/2" speakers and a 500/1 for the subs.
I just thought I'd throw it out there. People are always asking about stereos.
Related note: stay away from dealer upgrades.