WAY.

Benjamin's new favorite word these days is "way," as in "way hot," "way nice," "way yucky," or my favorite, "way yummy." He called me into the kitchen the other day, saying "Mommy! WAY yummy!" He was eating a peach, and wanted to explain to me just how good it was. He'll attach it to other adjectives too. I think we must use it when we describe things as "way too hot."
So I can't attest to the accuracy of this story, but supposedly my first words were "No WAY!" He hasn't figured that one out yet, though. I guess I was a lot more stubborn as a child than he is.