The MacBook Pro is riding the oldest case.
PowerMac G5: Jun '04
iMac G5: Aug '04
Mac Mini Introduction: Jan '05
Powerbook: Jan '01. Or if you only want to count the Alum Books: Jan '03.
Its getting close to 5 years on just the Alum design which has not been changed except for charging port, isight, and double latch in 4 and a half years.
Psssh... the Tit, which is basically the same thing is 6 and a half year. Over double most of the other case lifes. I think MacBook Pro are most in need of a new case. Especially since they have the largest problem with cooling, bad signals, lack of expandability, and prone to bending, cracking, dinging. All the other cases are pretty good. I mean their desktops, the cases dont exactly change much.