Sun has said it will add Gnome to its list of desktops distributed with Solaris. This is good news on many fronts. First, it benefits shops that use Sun and any other Unix or Linux desktop. The Common Desktop Environment (CDE, still the default desktop on Solaris) is not intuitive. Most other desktops share a small amount of commonality, but Sun has taken the CDE in a different direction.
The second beneficiary is the open-source community. The Gnome interface has grown into a useful windowing system and the Linux community has taken to it. Sun distributing Gnome with Solaris (as opposed to shipping with its upcoming Linux release) amounts to a large commitment by a major vendor. That should increase the work on the Gnome project and put an increased quality and usability requirement on the interface.
Gnome is a high-quality desktop. I use it every day, and the problems I have are not with windowing. Sun has spent years building a reputation for quality and stability, and the vendor would not get involved with an unstable project.
Sun isn't the first company to integrate open-source software into its offerings, nor will it be the last. But Sun's weight adds credibility in a way that other vendor endorsements can't.