Red top, blue top, or yellow top?

 

Depends on what you're looking to get out of it, really. What kind of electrical demand do you have in your ride (toys and whatnot)?

 

The blue seems to have the highest CCAs and reserve capacity but they have various sizes of each color now.

The question can easily be answered by reading through their website. They have comparisons for CCAs and Reserve Capacity within each color.
http://www.optimabatteries.com/home.php

 

Blue has a good discharge rating. Good for sitting in a parking lot with the music going for hours
Red has a high output. Good for high powered output with good powerful reaction times on the demand of your equipment

Yellow is balanced between the two.

Its the same for all batteries. Blue is usually referred to as a marine battery. Red is high output and yellow is feneral purpose.

I would go with the advanced auto parts special unless you need to mount it upside down or something crazy like that.

 

The Red is a standard automotive dry cell battery. Yellow and Blue are both deep-cycle, which means they can be almost completely dead and will still take a charge. The Blue is salt-water resistant. Red costs the least, Blue the most. The only difference between Blue and Yellow is the salt-water resistance.