whats a good battery to buy?

I buy the optimas , I buy them from the same place, and have them in two or three vehicles, they have a 3 yr warr, and if you take it to the parts place you bought it from and they hook it up and it dont read(really dead) they will just hand you another, its also come in handy that i bought one a yr after the other cause I knew the one ran out of warr, so i told them it was out of the other vehicle, funny how i was just happening to be driving that vehicle with the dead battery to the store :D