Cosi - pronounced cozy, just recently opened in downtown Seattle next to Macy's. We used to live in Chicago and we would go to Cosi all of the time - I was so excited when I saw that one opened here.
It is a relaxing, cafe style, modern atmosphere. There are tables, or soft chairs and couches if you prefer. The food is extremely fresh - great gormet sandwiches, flat bread pizza and salads. But my favorite has always been the dessert - S'Mores. That's right, you can toast marshmellows and make S'Mores either with traditional graham crackers or giant oreo cookie pieces. I loved this so much, our friends purchased us our own S'More maker from Cosi that we still use all of the time.
It is also very baby friendly. I take my baby in their all of the time. They have high chairs, a changing table, and the atmosphere is fine for a baby. It is counter service so you can eat quickly and leave if baby gets antsy.
I did have trouble finding out how to get in with my stroller due to all of the stairs. Next to the Macy's entrance on 3rd avenue, there is an entrance to Cosi with a small handicapped elevator lift. I just go in there with the stroller and it takes me right up.
Next time you are downtown, I would give Cosi a try and definitely have the S'More's (don't let baby get too close to the fire:)