1. a bestskinsever or invisible shield (to protect from scratches)
2. buy a bigger hard drive and pay for authorized apple service provider to install it (so warranty is not voided) (upgrading the hard drive won't void the warranty, but if something does go wrong, and the hard drive is the problem, then you're out of luck)
3. a thin case (marware for frugal, but sleek, and booqbags if you want to spend money for spending's sake)
4. wireless keyboard and mouse
5. elevator or other stand for ergonomics
6. memory card reader that fits into the expresscard slot
7. 3 year applecare!