After switching employer I'm no longer tied to Windows Vista & Red Hat. Truth be told I'm quite happy on Red Hat, Vista less so. Anyway, my new setup is Mac OS X Lion & Ubuntu. I use Lion on my personal computer so that is no problem. Although from a developer perspective OS X isn't Linux like Red Hat, but once you learn the tweaks it does play ball.
As for my new Linux workstation I was encouraged to use Ubuntu. I tried Ubuntu briefly at University and didn't really see what the fuss was about. If anything I found it really annoying as everything I wanted (developer/sysadmin tools) were not installed. However, a new job means an open mind and I've landed with Ubuntu 11.10. I had heard about Unity and indeed it is an impressive desktop, which has been a pleasure to use. Ubuntu 12.04 is out in a matter of weeks and will feature HUD, which again is very nice, but is nothing new over one of my favorite Mac apps: Alfred (Like QuickSilver).
Mountain Lion has just been announced as well. So there will be plenty of activity for my operating systems this year, just after I've got them both setup the way I want them!