I would suggest a good dual purpose battery, that way you get the best of both worlds. Good cca and ahr. Something like the 31M-800, or if funds allow, a similar size Extreme series. - 34M-PC1500, or if you really want to dig deep a 31M-PC2150. But then the likes of Lucas, Exide and Numax all make similar capacity dual purpose batteries at a fraction of the cost of an Odyssey, but do you really get the same quality and performance?? Not sure, but my Numax 120ahr dual purpose set up (1 main and two aux) has lasted several years, without one failing.
What ever you end up going for, if you're only going to run one battery, put an auto voltage sensing isolator between the battery and any auxiliary load, especially the fridge, or, at some point, you're going to end up with a flat battery.
