Microsoft's next generation OS, Longhorn has a lot of features that make it compelling to computer users everywhere.  But element of it that is looking very exciting is the ability for developers to create software to customize it.  Longhorn comes with a new rendering engine called Avalon.  It's through Avalon that Longhorn will be able to deliver things like Aero Glass, a new user experience that includes title bars with semi-transparent borders.

The ability for software developers to integrate into Longhorn (without compromising security), at this stage anyway, looks very promising.  When combined with the impressive list of technologies in Longhorn, users and companies alike will be in a very good place.  A place in which they'll be able to customize the next generation version of Windows to suit their needs.