Cloud Computing is coming and whether you like your own hypervisor there or not, desktop is definitely what Sun is poised for!
This now adds the ability to run 64-bit OSes on a virtual machine, an improved GUI on OS X and paid support subscription for its customers.
This new release comes only a few days after the release of the maintenance release 1.6.6 which already included some important fixes, like improved stability and performance on AMD CPUs that support AMD-V virtualisation, plus better SATA drivers, shared folders performance, improved support for recent Linux kernels, and some fixes for OS-X users as well. A full "change log" detailing the bugs fixed can be found over here.
Available in 32-bit and 64-bit editions, Sun's open source product available under a GPL licence allows running most modern OSes unequalised and itself runs on a wide range of host operating systems: Mac OS-X, Windows (32 and 64-bit), Linux, Sun's own x86 Solaris and OpenSolaris. Some die-hard OS/2 users have also donde a port of an older version.