Wonder of wonders. One of the interesting features of SANs in general, and iSCSI in particular, is the ability to boot directly from the exposed logical units (i.e. disks in SAN terminology). You don't need local storage. Why would that be useful? It's good because you don't need local harddisks anymore. You can keep and manae the data in the SAN cloud; backup, for one thing, becomes easier this way.

Boot from SAN was working for a while in Fibre Channel environments, but it was largely absent in the iSCSI territory in the past. Well, not anymore:

http://www.infostor.com/Articles/Article_Display.cfm?Section=ARTCL&SubSection=Display&PUBLICATION_ID=23&ARTICLE_ID=251922 

 Microsoft enables 'boot from SAN'
Microsoft announced today that it has worked with IBM to develop support for software-based remote SAN boot of Windows using the Microsoft iSCSI software initiator and standard network interface cards (NICs). Microsoft plans to publish the technical details of the implementation to help its partners develop iSCSI software-enabled boot.

However, note that this is not something that would would be able to try at home. It still requires special hardware changes.

"This is not a solution that can be put together by end users themselves, but by server vendors or independent software vendors," explains Dr. Claude Lorenson, group product manager for Microsoft's Storage Division.