sudden motion sensor? Let's not forget about that. It is the little details that Apple engineers and includes in their machines that make them different and IMO a better long term computing platform.
Apple's macines are built for the long haul. I have a G4 450 single proc. that my 5 year old son still bangs away on. In comparision, my brother inlaw only expects to get 3-4 years tops out of his home built computer that he just spent $400 (us), and an afternoon putting the thing together and setting it up. By the time he builds a couple of these, plus software and set up time, not to mention troubleshooting windows, the $2k I spent on my Powermac doesn't seem too bad.
Sorry, but 2 things not considered are TCO and longevitiy.