So is it worthwhile to enable and use hybrid sleep on a Vista notebook?
Yes, it won’t hurt anything.
Some users will immediately decide that sleep means sleep and hibernate means hibernate and will disable hybrid sleep as soon as they can. I’m leaving it enabled on my notebook because of those times when I pulled my old XP ThinkPad out of the sleeve and found it warm or dead. It’s a bit of a mixed bag, but if I put the notebook to sleep and forget about it, it’s nice that Vista will notice and hibernate the machine well before the low or critical battery level happens.
That said, I did not get hybrid sleep working well right away. The ThinkPad was losing 24% of the battery overnight when set to sleep. Something was waking it up during the night. First, I tried disabling “Allow this device to wake the computer” for the wireless network adapter in Device Manager. That had no effect. Then I noticed that Windows Update was set to go off at 3:00 am. Changing that improved things, but the battery still went down more than I thought it should.
Ultimately the problem turned out to be Kaspersky Antivirus. I set it to check once per day at 10 a.m., and the ThinkPad made it through the night with 100% battery.
I still select Hibernate when I know it’s going into the bag for a day or two, but I select Sleep if I think I may return to the notebook within an hour or two. In the last almost a year that I've had this ThinkPad, I haven’t had the notebook hang up once when going into sleep or hibernation mode, and for that, I’m quite pleased.