I haven't used it myself yet, but I have heard from many different sources that Quilter's Dream (Request weight) cotton batting is excellent for hand quilting.
Have also heard that Fairfield's cotton batting is excellent for hand quilting IF you pre-soak it to remove the binding resins (which are good for machine quilting, but make the needle stick when hand quilting). This was the cotton batting preferred by the original Roxanne of Roxanne's needle fame; I took a hand quilting class from her a year or two before she died.