Speaking as a mom of twins and a grandmom of twins, you are on the right track to make the quilts different. Since you do not know the sex of the babies, I would avoid floral all together. There are so many cute stripes, polka-dots, tone on tones, or even Moda solids to work with. Has the mommy to-be registered online? That is usually the first place I go before making a baby quilt. See what the mommy's taste is and go from there. I've seen so many interesting trends: yellow with grey is really big right now. So is orange with baby blue, or aqua with red. If you can't figure out what the parents want, if you go with any of those 3 color combinations you'll have a winner.