whats a good battery to buy?

If your car does more sitting than driving (not a daily driver) try a deep cycle marine battery. The only down side I've found is the need for post adapters to use them in a car. I've got one that has been around for 10 years and has been through 3 cars. Only have to charge it if the car has been sitting more than 4 months. One hour quick charge and it's good to go again. May not be cool and the latest hip gadget but it works. Just my $.02.