I will be buying a new computer around September (currently have a G5 iMac with Leopard). In addition to OS X, I would like to run Windows 7 and Ubuntu on it (my wife bought a 15" Dell Inspiron a few weeks ago and I'm really impressed with Win7). Now, the easiest way to do this, would be a Mac Pro with 3 hard drives. But that's a bit on the expensive side. I was thinking Mac mini with external firewire hard drives (like the ministack). I would like to be able to boot up natively in any of the three operating systems, but would also like to run Win7 and Ubuntu in a virtual environment from within OS X (using either VM Ware, Parallels or Virtual Box). I haven't decided on the Mini yet, could be an iMac or even a 15" MB Pro but that doesn't really change the "equation"... How difficult would it be to set up a configuration like this ? Also, can I just go out and buy an OEM version of Win7 Ultimate or will I have to fork out extra for the retail box ?