the folks at Networkcomputing.com have been putting the Longhorn Beta 3 through it's paces, see what they say:
"After weeks of hammering, picking and probing, we walked away impressed. As Microsoft promised, Longhorn offers significant security improvements in the areas of setup and configuration, OS modularity and client health detection, plus an enhanced firewall and a new IP stack.
More subtly, you'll find the kind of attention to security details that Microsoft products have lacked in the past. Take, for example, the best little feature that you may never even notice: While the Initial Configuration tasks wizard is running, the server cannot be accessed through the
See the fill story here http://www.networkcomputing.com/showArticle.jhtml?articleID=196900562.