"I found Windows 7 to run quite well as a VM under both
MEPIS Linux and Windows XP SP3. As far as I'm concerned, the
Windows 7 beta actually runs better than Vista SP1.
"You should be aware, though, of some fundamental differences
between running an operating system in a VM and running it
natively. The most common problem is the inability to use the
higher performance features of graphics, audio or network cards.
That's because, like most virtualization software, VirtualBox
provides the guest operating system with a virtual VESA-compatible
graphics card, a virtual Intel ICH AC '97 audio and several virtual
network cards. In short, your virtual Windows 7 can't use your
high-end graphics card or what-have-you because only the host
system has access to it, not the guest operating system, which must
use virtual drivers instead."