Generally speaking, 6 volt golf cart batteries are considered the best "standard" battery  for use with solar panels or boondockiing. Certainly there are other(lithium, AGM, etc) batteries that are longer lasting, but also much more expensive and require additional electronic changes to the on board charger.

We purchased 2 6v golf cart batteries at Costco for about $110 each. they have 215ah each. Our 100 watt Renogy suitcase system will keep them charged as long as we can get about 4-5 hours of sun. We boondock a lot and are power misers-no electric tongue jack, LED lights, radio power switch, etc.

There will probably be lots of personal choices and observations on this topic. Everyone has their favorites and opinions.

Vann

Originally posted by Buffalohunter are there batteries that are designed to work best with a solar package. I was told that “ these batteries are meant for solar panels so they are so much better than regular car batteries”.  It all sounds good but is it true? That being the case should I convert to this kind of battery...is it that much better...what am I missing?

Only partly.  There is no such battery that is better to use with solar panels.  Your charge controller will charge and protect the battery, with the right settings. 

There ARE deep-cycle batteries that are better suited to the charge/discharge cycles a solar charged system sees and those do not lose life from deeply discharging them (within limits) like a car starter battery would.  Often called trolling motor batteries, these batteries can be discharged to about 70% without significant loss of life, while a starting battery is somewhat damaged by a 50% discharge. 

No lead acid batteries should be taken below 50% state of charge on a regular basis, it will significantly shorten their useful life. That includes deep cycle batteries. As for AGM (absorbed glass mat) or gel batteries (generally known as valve regulated batteries, no lead acid batteries are actually "sealed") you should consider those if you can't trust yourself to regularly (at least monthly) check the water level in standard flooded batteries and add distilled water if needed. If you can do the checks, then the flooded batteries are your best choice due to lower cost and because you CAN add water to them if they are accidentally overcharged. You can't do that with valve regulated batteries so if they get overcharged (say because your battery charger doesn't reduce voltage when it should (it happens) then they become expensive boat anchors. 

If you are boon docking for several days or more most folks find that two 6V golf cart batteries (case size GC2) are the most cost effective choice, assuming your tow vehicle can handle the additional roughly 60-70 lbs of tongue weight. 

The very best (and lightest weight) is a lithium ion battery, but they are still pretty expensive and also require that you change your battery charger and, if you want to charge from your two vehicle, add a dc to dc converter to do that.