Our sales guys use to drop their Dell's on a very regular basis, it was one of the resaons we use to have Dells, they can stand up to it very well. The case would get a crack or two around the thin areas, but in most cases it was all cosmetic.

The one weak point, if it was closed at the time it usually sheared the case closing latch off, easiest way to tell if they have tested gravity with it, if the case latch was busted.

One of the testing sites, don't remember which one, probably cnet, actually includes dropping onto a hard surface as part of their tests.