If you have no interest in virtualizing Windows then this won't be of much use to you. First class support for Linux is limited to Suse and RedHat Enterprise.
However, if you're a Microsoft shop and want to virtualize Windows (be it for production, testing, or development), it's a huge boon. Hyper-V even supports some awesome features like live migration (moving a VM from one host to another) with mere seconds of downtime. Similar features in VMWare cost thousands of dollars.
At Loopt we're going to be using this extensively for development.
Hyper-V is a bit of a pain as it doesn't let you over-commit on memory.
VMWare ESXi looks like a much better bet - I'm currently thinking about moving 40+ VMs in a development environment from Hyper-V to ESX so we can run more of them at the same time.
Actually, with Windows Server 2008 R2 SP1 it will add dynamic memory which is the same as VMware's memory overcommit as well as RemoteFX for 3D graphics display for virtualized desktops.
However, if you're a Microsoft shop and want to virtualize Windows (be it for production, testing, or development), it's a huge boon. Hyper-V even supports some awesome features like live migration (moving a VM from one host to another) with mere seconds of downtime. Similar features in VMWare cost thousands of dollars.
At Loopt we're going to be using this extensively for development.