Amazon and Play both have VMWare Fusion 3.1 for this price, when I checked Amazon last month it was ~£60. Basically enables you to install Windows (or pretty much any other OS) on a Mac as an alternate, and switchable, OS. Note that Windows isn't included, so may be more use to anyone with a spare license kicking around.
Play URL is: http://www.play.com/PC/PCs/4-/12160823/VMware-Fusion-3/Product.html
EDIT: Also contains a year's subscription to McAfee for your Windows partition!