2nd that!!!! also you may find the SuperDrive cheaper on Ebay or Craigslist,....
I've got a MBP Unibody and a MBA for travel and find myself using the MBA more often. I've blogged about it and it'll def work as a primary computer with a note that the fans will blow on any processor intensive tasks. In my setup, I render movies with the MBP and write with the MBA.