For more than 10 years, I've been meaning to try out Solaris, to broaden my system administration experience (most of which is currently with Debian, Ubuntu, and OpenBSD), not least because of the features that Solaris pioneered, such as ZFS and DTrace.
On top of that, OpenSolaris now has a user experience that was "inspired" by Ubuntu, and looks like a fairly credible desktop system too (with my favourite theme, Nimbus :-P).
There is only one real hurdle, for me: the console has no Dvorak support:
It's true that in X, I can simply use
setxkbmap dvorak (and it works when I tested it on OpenSolaris 2008.11), but there are some maintenance tasks that can only be done in single-user mode. It would be most ideal to remove the "cognitive dissonance" of using the system, by not having to switch back and forth between the two layouts.
 In the same way that CNProg was "inspired" by Stack Overflow. :-)