I chose Ubuntu specifically to avoid Windows. I have never been a Windows user, except briefly five years ago when I did an OU course and their online stuff required it
at that time - don't know about now. Anyway, I set up Boot Camp, got Windows XP and had a nightmare of a time with it. Can't remember details - just the feeling of despair.
Plus, Ubuntu is free! I quite like what I've seen so far. I won't be doing anything other than Folding@home, which I now have up and running after a goodly amount of help from the F@H forums. That is another high bar to clear. I've found that nothing about F@H is intuitively obvious. I had to have help getting it running on my iMac in the first place.
I will say that my new machine is fast, and some. There will be faster ones out there, I know, but compared to my Intel iMac, it just chews the WUs up at an incredible rate.
I think I was lucky to have had such an easy ride with all this. Lots of help and advice online. No component failure during and after building the machine. I am at the place I wanted to be. Eventually I want to disconnect and put away the monitor, keyboard and mouse - and internally disconnect the optical drive to save some electricity. 'Headless' - is that what they call it? Then I'll try and get to grips with ssh - am I using the correct terminology?
I haven't taken any pics. I'm loath to be considered to be blowing my trumpet too loudly because it's fairly simple build as things go.

I've never been a gamer, so a graphics card isn't on the horizon. I suppose I'm very humdrum basically, but I now have exorcised this bee from my bonnet.