I love my JuJuBe bag. Well made with lots of thoughtful details (mommy pocket, crumb drain, etc). They have tons of cute prints and different sizes depending on how much stuff you plan on carrying with you.
I agree with PP that a bag with lots of pockets is a must. The first bag I had didn't have many pockets and was mainly just a big open space, and it was very annoying to have to dig around to find something.