Mac OS X, Windows Vista and Ubuntu Linux together in Parallels worlds

So I bought two seats of Parallels a week or so ago. I couldn't resist: It was buy one, get one free. (And still is through December 31st.) Now my desktop Mac at work and my MacBook Pro drive the latest versions of OS X Leopard, Windows Vista and Ubuntu Linux, all from the same desktop, running in ... parallel. Who needs to choose between Mac and PC when there's Parallels?