These Bazookas are great, and are kind of in between prices of what you have posted. They are $349 a pair from Crutchfield:
Bazooka Tubbies
If you want to go all out, this Infinity is the best system, as it comes with an amp, incredible speaker clarity, and a PA system so you can communicate with your skier, or anyone else on the water. This one is a little pricey, but worth it if you are serious about your sound. It's $1000 from Crutchfield:
Infinity system 
