That is Solaris 10 Update 7, with :
Let me say it upfront though, it has been a while since I had myself played with a Solaris 10 release. Since Sun came out with its own (supported) OpenSolaris.org distribution named OpenSolaris --there are 10+ OpenSolaris.org distributions to date by the way, including Nexenta, BeleniX, MilaX--, my Solaris distribution of choice has been OpenSolaris instead. I run it inside VirtualBox on my Mac laptop. So, because it was a while, I decided to download and install Solaris 10 05/09 as a personal experiment.
As a first reaction, I can report that it is hard to go back --from OpenSolaris to Solaris 10. Or, to put it in a positive light, OpenSolaris has really succeeded in addressing the gaps of Solaris as a general-audience (desktop) operating system!
First, OpenSolaris downloads in one third of the time. No wonder, OpenSolaris happily fits on a CD while a Solaris 10 image is 2.4GB big, as you can see below. There is no magic though, the Solaris 10 DVD comes with a full server-side distribution while OpenSolaris will require additional downloads. Still, the first impression remains in favor of OpenSolaris.
$ ls -l
-rw-r--r-- 1 fparient admin 719087616 Apr 27 2008 os200805.iso
-rw-r--r-- 1 fparient admin 720697344 Nov 26 12:25 osol-0811-rc2.iso
-rw-r--r-- 1 fparient admin 2330460160 May 12 19:33 sol-10-u7-ga-x86-dvd.iso
Second, OpenSolaris installs smoothly: fast, without error, and with only a few questions asked. Somehow, the Solaris install failed twice for me before I could get it right, I had to answer many more questions, and the actual installation of files took a long time. Sure, I ended up with a full server distribution but it is only over time that I (may) realize the benefits.
Lastly, OpenSolaris looks nicer. Okay, this is a matter of personal taste, but I do think the OpenSolaris windows environment is slicker. See for yourself.
The next release of OpenSolaris is planned for June 2009 by the way. I am really looking forward to it!