One big advantage of streaming is that IT has fewer images to maintain. That benefit applies in spades to application streaming products from Altiris and Microsoft.

For example, CSU's Washburn says that Altiris' Software Virtualization Solution solves a long-standing annoyance with SPSS's statistical software. Each year, a new license key is issued and must be updated at every user's desktop. But with Altiris' software, Washburn simply updates the server copy, which is provisioned to users automatically when they call the application.

Although the technologies from Ardence, Propero, Stream Theory, and Wyse centralize applications and data, they also let users store data locally as well (a PC's C drive is remapped to become its D drive when their software runs). Moreover, because Altiris' and Microsoft's application streaming tools let you set up applications in their own virtual layer or session, IT can avoid the regression testing across the whole application set whenever a program is modified or added, says Russell Investments' Nelson.

With the solutions offered by Altiris, AppStream, and Microsoft, the client PC can have its own operating system and applications installed, while the server pushes centrally provisioned applications into local desktop caches. In this fashion, IT can distribute resources selectively. For example, Russell's Nelson installs Windows along with applications that act as extensions to the operating system (such as Adobe Acrobat Reader, Apple QuickTime, and Java) on local PCs -- plus Microsoft Office and a few other frequently used applications -- on local PCs. Then he uses SoftGrid to provision other applications as streams.

This selective approach can also help balance performance, notes CSU's Washburn. Were Washburn to deliver everything as streams, it would take client PCs five minutes or more to boot up -- a nonstarter. So he installs core applications on the PCs the old-fashioned way, using Altiris' remote deployment tools, and provisions less frequently used programs via application streaming.