I am not quite sure how measure. I would say around 20" at the withers, but he is much bigger than any of the other dogs from his litter.
I have had full sized Aussies before as well. Imagine taking that energy and compressing it to a singularity that is always ready to explode. That is Rufus and I wouldn't trade him for the world.
I've used gnome for years, about a month ago I decided to give KDE a try on my old spare laptop. Two days later it was on my desktop and work laptop. I am loving KDE.