Red Heart Super Saver may be rough to work with but after a few washings it's soft.
If you mind working with rough I'd say Simply Soft. If the store you go to has the Eco you can even recycle some plastic bottles while you're not using animal fibers.
I forget the exact amount of bottles in a skein but one of my waterbed afghans would sure put a dent in the landfills.
Petroleum based knitter, removing that nasty oil from the ground one skein at a time.