Deep cycle batteries
My own experience is they last a long time, but cost a lot. I do like the sealed/lighter aspects of them.
I've been using the Walmart EverStart MAXX Group Size 29, with outstanding results. At just under $100 there is no better battery for the money and has a full two year replacement policy. One set I have are going into their 6th season with three on the boat, one for the "house" battery and two for the 24 volt trolling motor.
Be sure to get the MAXX which is their premium battery. Actually read the reviews on the Walmart page and you'll see I'm not the only one having great luck with them. They are made by Johnson Controls, a company with it's headquarters in Milwaukee.