I would say most people shut down, rather than sleep/hibernate. Especially laptops, which are prone to heating up in a bag if they are left asleep, and which take just about as long to get out of hibernate as they do to boot anyway
What kind of crap laptops have you been using? I've got no less than 7 or 8 here, and they all use about as close to no power as you could hope (and make no heat) in sleep mode, and coming out of hibernation takes far less time than an actual bootup (not to mention the battery savings,) especially on older systems.
Fast bootup is nice, sure, but OSes and systems are stable enough to suspend/hibernate, and people do take advantage of it. I routinely hibernate my dual-boot netbook and switch from Linux to a hibernated Windows session and vice versa.