This is probably obvious but worth noting anyway: remember to do the snapshot before you start the VM. The expiry countdown starts the first time you boot the VM and is date-based so the VM will expire even if you only used it once.
On the other hand, having a snapshot in a booted state gets you up and testing much quicker for subsequent runs. Even if it will expire after a while, you'll get one hour of work in before windows shuts down, and then you just restore the snapshot again.
Really? I'm pretty sure at least one of the VMs was completely locked down when booted up after it had expired. Not sure which version of Windows that was, though.
That said, what I generally do is to simply suspend the VM instead of resetting it to the snapshot. Then when it expires I can still do a reset to the snapshot to reset the expiry.
I generally boot at least the IE8 VM up before using it in order to install basic things like the Flash player (to test the Flash fallback for HTML5 media players).
I think you need to do an import first, so it is faster to just rollback to a snapshot than re-import each time. I prefer snapshots so I can configure the network as needed for our corporate environment (saving me from doing that each and every time).
