If it were one of those old orange iBooks I could see durability being higher...those things are TOUGH. My new MacBook feels well built but not as heavy duty as the old orange one.
Computers in general seem sort of weak today. I have a couple of desktop computers as well--an old Windows 95 IBM, a Mac LC (in its box, this one's from when I was little), this old-school Mac SE that my dad had and gave to me (it's the kind with the black and white monitor and the little disk drive--I actually used it to keep track of baseball stats for a while), and this really old Toshiba computer from my grandpa that runs DOS. All of those look pretty well built, especially that IBM. (I still use the IBM sometimes since I have Excel on it).
At work we have these H.P. computers. They don't seem as bad as the Dells I see at the library though. Those Dell computers always seem to have plastic parts missing from them. The H.P. keyboard feels pretty flimsy though. My grandpa has a pretty recent IBM computer but I think I read in the paper that IBM isn't making computers anymore?
I have always used a laptop case with my computers. They've rolled all over my car and everything and nothing's ever been hurt.