My first quilt used polyester batting - it bearded like crazy, putting white pills all over the top. I used cotton for years because of that.
Then I used Mountain Mist Lite. It's thin, but no bearding. I've also been very happy with Hobbs Polydown. It's a little thicker so it defines the stitching better, and it doesn't beard either. If you're hand quilting I'd recommend either product.
Janet