I feel your pain. It feels like my little one has been sick all winter. The doctor says that this winter was really rough.
They are very clean at her daycare, and very careful with the handwashing. Better than I am, to tell the truth. The one thing I'm going to try is wiping her hands immediately upon pickup, before I hand her post-daycare snack.
As for the breastfeeding crowd- the idea that breastfeeding keeps your kid from ever getting sick is B.S. How do I know? My daughter is still breastfed, at 2 1/2. And she's been sick a lot this winter. So stop being so smug. I think it may be that moms who breastfeed may be less likely to put their kids in daycare or preschool.