My aluminum dock system is a Floe. It is a rolling dock system that my boys and I install ourselves every year. I am on the roughest part of the lake and routinely see 3 foot waves. The best part of this system is that it can be adjusted for seasonal water height differences with a cordless drill. There are no posts, just leg kits with a large nut on the top for adjusting the height. This and the 15 year warranty was a big selling point for me.
http://www.floeintl.com/docks.asp?pageName=rollIn&sm=1