Any of these look familiar?
http://www.drivers-software-download.org/tag/acpi-acpihidmapper

Not really, no :/

Hm, there's a 26meg "ZeptoMobileUtilities" thing, guess I ought to take a look at that - from the description it sounds like it's mostly useless (to me) OSD stuff etc. and not drivers, though. And apart from that weird ACPI device, everything else seems to be in order.

Have you installed specific motherboard drivers or are you relying on the Vista built in drivers? If you have only installed Vista setup drivers for the the mobo try going to the manufacturers website and downloading the latest motherboard drivers.

Specific chipset-drivers from intel, and their graphics drivers and wifi drivers as well. Can't remember if the realtek gigabit LAN was Vista built-in or if I had to install specific drivers. Iirc audio is vista built-in.

Turned out that the ZeptoMobileUtilities thing did have the ACPI driver, doh! I'm curious to see if this will fix the usb-device freeze thing, but somehow I doubt it (although there could have be some power management issue after hibernate because of missing driver, dunno).

Haven't installed the whole package though, there's no more drivers in Device Manager that are missing, and while there are other drivers in the pack, they seem to be related to battery status indicator, some specific multimedia keys (that already seem to work just fine), et cetera.

Yeah, but come to think of it, iirc I've also had weird ACPI drivers with ASUS motherboards until I installed one of the ASUS tools, hmm.

Too bad the driver didn't fix the freeze issue - did a clean reboot after installing driver... inserted USB device, worked fine. Did hibernate and resume, inserted USB device again - hang. Guess I'll try playing some sound in the background and see if that freezes as well, and then ask zepto if it's a known issue etc. *sigh*

I can't remember what the article (or the number) was called but I seem to remember an issue in an MS KB article on resumption from hibernation and USB. Might be worth a quick search.

I wasn't able to find anything interesting :/

I think I'll try wiping the xubuntu partition I also have on the laptop, and put XP64 there. Will be interesting to see whether I get the same issues then, and how it performs compared to Vista64 on the same hardware.