I'm coming up to five months usage of my Mac Pro. I long ago disconnected it from the living room TV and placed it on the high plateau at the back of my rolltop desk, hidden from view for the most part by my iMac. I am happily using wireless screen sharing to interact with it but I did order a ThunderBolt cable so that I might do so directly via Target Display Mode.
The screen grab shows what I am doing on my Pro. On the top left is Mathematica calculating an extension to A066364, something I have been working on for quite a while. I'm near 2000 terms and I have another two weeks to go before I reach 10^12. Below Mathematica is my Activity Monitor showing the top active processes. My Pro has only six cores but through some sort of doubling magic the sum of all processes can approach 1200% CPU. At bottom center is my dock, and behind it my Terminal window which I use only to run Dario Alpern's java factorization app. In fact, I have nine of these running (top and right) working on 120-digit composites. The seventh one, just above the Terminal, has found a 42-digit factor (highlighted in blue). Bottom right is a hint of my Finder/desktop.