I like W&N 100% cotton batting. The only thing I'd use besides that for a bed quilt would be washable wool.
In my experience, the shrinkage issue can be reduced in 2 ways:
1) Make sure to only wash in cold water & only dry on No/Low heat or lay flat to dry.
2) Quilt farther apart (check your batting about how closely together it needs to be quilted)
I also pre-soak my batting to help shrink it a little bit before I quilt with it. I do use poly batting for home decor items & wouldn't have an issue making a wall quilt with it unless I had put a lot of work into piecing/applique. I've always been told that any time you start mixing and matching materials (cotton fabric with poly batting, for example), it makes it slightly less durable. I believe that to be true, but sometimes you just really want to get something done without spending every last penny you have on materials. I made a table runner about a decade ago with poly batting & a poly-cotton thread. Recently, I started having some issue with it when I pulled it out of the dryer, but I guess for what I spent making it, 10 years is a pretty good run. And I think I can probably re-quilt/re-bind the problem areas & get some more life out of it.