both.... If I'm planning a quilt project to be a gift for a particular person's special event, I do choose the fabrics just for the recipient. If I just want to try a new pattern, I have fun with my stash and maybe one new fabric I'm itching to use. I almost always create my borders when it's time to make them and I can see the pattern all done; I usually do something new I've wanted to try on a border.
I like both; quilting for a purpose and quilting for a surprise.