Get the cheapest one with a decent warranty (2-3 years)

Go online with a coupon code (Right now Advance Auto Parts and Pep Boys have online coupon codes for 20-25% off...) Order online, pickup in store hours later.

Current coupon codes:

Advance: P20 (20% off all orders)
PepBoys: SWING25 (25% all orders over $100)

I got my batt for $86 installed at Pepboys. Optimas are nice and all, but they fail too...