My 1st gen MBP unibody 2.53 C2D 15" has survived being dropped in a parking lot(needle nose pliers repair of case by me), near total immersion in water by my 5 year old son(took over a month to dry out and turn on again), and my wife having every app in the world open at the same time with fans going full blast for 8+ hours a day. She is going to use that one until my latest cMBP gets too far behind the times.
Heck, we still have a 2006 15" 1.83 CD in a open area that is still in use for simple browsing.