I have both a stash and projects. If I see fabric that I love (mostly batiks) and especially if they're on sale, I'll buy them. I'll also buy particularly sale fabric for projects that I would like to try like stack n whack and "Wonderful 1 Fabric Quilts" projects, where I paid $2-5 per yard for fabric.
I am getting more selective though as time goes on, since I know I can't buy everything.