Backpack or other safe carrying/storage option. No question to me. I didn't leave the store without one when I bought my first SLR. I had one on hand before my 7D showed up.

But really, you'll want most of those on your list.

My order would be:
  1. Back pack
  2. Lens cleaning cloth/solution...lens pen, Giottos Rocket Air Blower
  3. Depending upon the price of your lens, a high quality (B+W MRC) UV or clear filter (basically, if lens is worth protecting...protect it)
  4. Memory back up system. As mentioned above, you can either do online or external hard drive
  5. Second/back-up battery
  6. Fast memory cards
  7. Understanding Exposure by Bryan Peterson
  8. Tripod or at least a gorillapod
  9. External flash with a head that can swivel.