If I were to buy just to build my stash, I would stick with blenders and solids. Unless you have a humongous stash, you will have to buy specific prints/colors for a pattern...at least most of the time. A bargello I recently finished required 24 different fabrics, and while I could pull a few from my stash, I would guess that I ended up buying 75% of them (over a period of several months and quite a few road trips to different stores looking for the perfect shade teal). When I have spare cash and a 50% off coupon to JoAnn's, I try to buy the Kona cotton solids for my stash because I know the quality is good and I will use them with most of my quilts.