My starter battery could use replacing, and I'm thinking its a good time to
do some rewiring and install an aux battery at the same time.

After looking at the whole optima/deep cycle battery situation, I'm tempted
to just get two of the walmart everstart plus group 41 batteries, and use
the second one as an aux battery (with the hella battery relay setup).  I'd
be interested to hear what people think of this idea.  (Especially if you've
tried it!)

I don't intend to run the fridge off the battery for any significant amount
of time; I want the aux battery for the stereo/cabin lights/etc/ and 12v and
110v outlets (I'm going to install an inverter) to use things like
laptops/music players/fans/etc.

And, just to confirm it... there really aren't any deep cycle group 41
batteries out there, right?

Thanks guys,
Wes