Wal-Mart Maxx Marine and Interstate batteries seem to be the most popular for trolling motor applications. My Son and I have used the Maxx series for several years with good results. I like knowing I can get one replaced 24/7 at any Wal-mart if one goes bad. Consider a Marine/Starting battery for the big engine. They have plenty of starting power and more reserve for your livewells and sonar when the engine isn't running. I would stay away from the regular brand of Wal-mart batteries, don't hear too many good things about them other than they are inexpensive.
Try not to run the batteries more than 50% down, charge them immediately after use with a modern charger and they should last for years.
