This is a great thread for beginners!!
Most of my important ones have been said already, so I'll just add to all of the above.
Here are my "must-haves" in no particular order except for number 1:
1. Kitchen Aid Mixer!!!!
2. Fondant Smoother (not just for fondant, but also for smoothing buttercream with papertowels)
3. Blue Shop Towels (if you live in Canada, we don't get Viva here
4. Pizza cutter for playing with fondant
5. Letter stencil (if you're nervous about writing)
6. Silicone spatulas
7. A good camera to make your own cake album
Hope that helps!