Sleep/hibernate host machine without bothering about virtual machines?

I have a couple of workstations (Windows Vista, 7) used to host virtual machines using Virtual Server 2005, Virtual PC 2007, or Virtual PC for Windows 7. If i want to sleep or hibernate the physical hosts, I tend to get paranoid and save the states of the virtual machines before doing so.

What I would like to know is there any adverse effects if I choose not to care and just immediately sleep the host?

I use XP Pro workstations and VMWare, and I suspend/hibernate the workstation regularly with no special attention paid to the VMs. The only adverse effect I've ever seen has been the workstations time getting further screwed up (For application reasons, I can't have them sync their time to anything).

When I put my host PC to sleep with VMs active in VirtualBox, they're automatically paused before the host system goes to sleep. As a result, the guests recover from a sleep/wake cycle exactly as they do from being paused. (Occasionally I have trouble with the clock not updating, but this is likely an issue with the VirtualBox guest additions.)

A bit of experimentation will probably show if your VM software does the same.

The standard answer in IT, it depends, applies here. Cursory searching shows people who had no problems, as well as people who had their guest VMs hang. My best bet is to try it and see; rollback is your friend here.