You have tons of options many of which are good/great products and will result a great system.
I personally like the sound quality of JL speakers. My opinion is clean great sound go with JL. Great sound but very loud at a distance then Wet Sounds. If you want JL to play loud and clear go with larger speakers and more of them. The JL M880 is a great speaker as well as the M770.
Amplifiers, there are lots out there. My opinion, buy a well known brand to match the channel and wattage you want and you will be happy.
Head unit. I really like Fusion. You can set up the wireless network and run the remote of any android or apple device. If you want remotes mounted they offer that too. You can hook them up the your Nav system. Blue tooth, remote iPod drawer if desired, dvd if you want to hook up to your AV system. Lots of options with the zoning which i don't know if i could do without now.
Worst part is the installation of all this. None of its hard just frustrating at times. My suggestion is buy once cry once that way any installation doesn't have to be redone later if you choose another route.
Some really personal advice. It has been my limited non professional experience that money spent on speakers is easy to hear / notice vs the other stuff. And I like to run more power than the min recommend wattage. I run all my M880 with JL amps bridged to 200 watts i believe it is. Doesn't mean I'll use every watt but it does make a diff in the sound quality even at low level volumes. I am not a big proponent of the speakers all being a ear height. I have been on boats with 4 speakers, 2 in the roof and 2 in the side of the hard top and once the volume is up, a conversation is almost impossible to have on the boat, yet the stereo can hardly be heard on the dock or floating behind the boat. if you install more speakers than the typical stock 4, down lower like foot level is my preferred placement. The volume can be turn up to hear on the dock and its less intrusive for the people on the boat. This is not a perfect scenario but it is much more user friendly environment in my opinion.
Good Luck, No matter what you choose if it sounds good to you and your happy then its a win!