I do not buy "collections". I have a really good sized stash so I can often make whole quilts using that.
However, if I were to purchase all new fabric for a quilt----I would look for a fairly large scale print for the border that I loved. Maybe choose a couple more fabrics from that collection but then would walk around the whole quilt store looking for fabric that would work well with the big one. If it has those little dots on the selvedge, it is very easy.
The pattern of the quilt would help determine what type of fabric I would purchase.