I'm looking for a set of 6.5-7.5" coax or component marine speakers in the $100-150 price range. Any suggestions? They'll be mounted in 23' cuddy cabin and powered by a 50x4 Clarion headunit.

 

I have two sets of the Polk Audio DB651 in my boat and they work and sound great. Mine are powered by the headunit, forget what it is at the moment. They are marine certified. For about ~$60 a pair you can't go wrong.
http://www.amazon.com/Polk-Audio-6-5.../dp/B000P0PF9G

 

I've used the same Polks in our boat and they've worked great!

 

Are you guys using the Polk db651 in saltwater? Are they in a wet or dry location? How are they holding up?

I looked at those but was hesitant because the rear is not sealed.

I've also looked at the mm651um (ultra marine) which has a sealed back as well as the Alpine marine models.

 

Mine are used in freshwater, two seasons now. I have an open bow Bayliner 175, so the front ones do get hit with some moisture. The rears ones are in the rear corners and have seen moisture as well. The backs do not get wet in my install. As of now, they look and sound good as new.