Originally Posted by Jafro

If you're looking for one to fit the factory spot, go with an Interstate battery. Great warranty, and IMO, the best battery buy. I've had 2 cars with Interstate batteries, and never had battery-related electrical problems.

I think your biggest concern should be "WTF has started draining my battery with the car off?"

Put a 12v test light between the negative post of your battery, and the negative battery cable. If it lights up, you've got something draining it with the car off. Pull all your fuses one at a time until the light goes out.

If it stays on during the last test, you have more than one circuit draining the battery. Pull all your fuses and replace them until the light comes on. The circuit that lights the test light is the one draining your battery. Check your wiring. Keep checking the others to find the other circuit. It takes some patience.

If it doesn't light up, and you don't have an alarm or aftermarket electronics installed, then check your alternator's wiring, and all of your engine's grounds.