I generally use 100% cotton for the tops of quilts just because I like how it feels.
Most of my thread comes from Connecting Threads but I have a lot of different brands that I use...some cotton, some polyester, etc.
Right now I like the Fairfield batting called Toasty Cotton (medium). I like how it feels in a quilt.
I just use what I have to get the job done.
So, I say I am not a purist.