I would suggest:
Optima Battery Model: D31M
http://www.optimabatteries.com/optima_products/bluetop/specs.php
Capacity: 75 Ah
http://www.amazon.com/Optima-Batteries-8052-161-BlueTop-Purpose/dp/B00099DW6G
$230.49
A classey solution to be sure, but I believe that our FRiend was looking to keep initial cost as low as possible, thus the $60 battery vs. the $ 200+ battery.
They’re both there on the shelf at Costco, and they both carry the same warranty.