The links on the right are resources for cake decorating, etc. Confectionery House has a lot of wonderful things, including really nice cupcake liners. For chocolate cupcakes, I love the brown cupcake liners. Red velvet cake looks great with their red liners, too.
Pfeil and Holing has all the basics like chocolate fondant and lots of pre-made and inexpensive roses and other flowers.
Cupcake Tree has a variety of really cute tiers, and Sugar Craft has a variety of styrofoam tiers that are very easy to decorate by pinning or gluing ribbon to the leading edge of the tier.