I've carried a Dell and a couple of Macbooks (pro and air). No hard drive issues with any of them, but the power button and the indicator lights on the Dell eventually got flakey. I don't think it had anything to do with commuting.
The Macbooks handle sleeping much better... or should I say handle waking up much better.
I can't recall either a modern Dell or the Macbooks ever spinning up a drive while sleeping, - unless they weren't really sleeping. I've seen it happen in older laptops.