My wife still uses an old G4 power mac as her main laptop. Sturdy little beasts. Outlived pretty much any other laptop she's had.
I have one of the first Intel MacBooks. It's my beater laptop, and has seen a lot of travel miles both in cars and by bicycle. It's been dropped, sat on, and my cat likes to sleep on it at night. Still solid and works like a charm.
Meanwhile my Dell laptop that I use for work and spends 99.9% of it's time on a desk feels like it's about to crumble whenever I pick it up. I can't imagine it surviving the travels the MacBook has been through.