In my opinion, wool is by far the warmest. It isn't that much more expensive and to me ('cuz I'm cold), is well worth it. The key is then, though, to not quilt very much or really, the best for warmth is to just tie it! It isn't as 'showy' but for snuggly, it is wonderful. Then if you put a heavyweight flannel on the back, it is great and the flannel keeps it from sliding off the bed as well. My mother (who has passed away) made one of those for us when we got married and I have 2 more since. (The old batting can be reprocessed at a woolen mill) It is my warm, useful quilt:-)