let's see
$1300 Pb
+87.25 (6 months of applecare beyond the 1 year warrenty)
+79 (Extra power adaptor)
+40 (Tom Bihn Case)
+X (for RAM, hard to estimate, so let's say I throw the extra 128 in for free

)
+131.96 (9% Chicago sales tax on the hardware and service)
Total:$1638.21
Admittadly, you get the fast proccessor and a bigger hard drive, but most people who want a sleek portable machine to surf the web, and send emails, don't need all that power.
Funny that I actually thought about how I priced my own computer. Isn't it?