I pile up fabrics to my stash, usually buying at least 1 yd, if I really love it, I get 3-4 yds. That's usually enough for bigger quilts too, and occasionally I donate some to my mom if I can't come up with a good project and she has something on mind.... :-)
Occasionally I buy charm packs or fat quarters as far as the precuts go but I have found it be more useful to have fabric by yard - there is always some use for it! More than once I have gotten an inspiration from my fat quarter stash, just to find that I would need a few certain color fat quarters more .....