I'm currently running a VMWare virtual machine, with Wow client and HB running fine. My machine is pretty high spec, but the graphics card is about 5 years old, so it doesn't require hugh graphics capabilities. Just remember to turn the graphics setting down to minimum, and vsync OFF. I'm running through a VPN connection, so the mac address and IP on the virtual machine are different to the host/main computer.
All seems to work well enough - although running more than one virtual machine might be tough on the computer! One thing - I tried Virtualbox and VMware, and found 3d performance in VMWare much better. I do get occasional crashes in the wow client (often in Stormwind, which is annoying), but it's pretty cool the way I can shutdown the VMWare screen, and leave my virtual machine running and botting in the background.