I've chosen Mint with the Cinnamon desktop. I liked XFCE when I tried it on a lower-power PC a very long time ago, and most of my Linux experience comes from Ubuntu in the Gnome 2 era, so those options are very nice to see from the start, but I specifically want to check out what Cinnamon has to offer.
A couple of minutes in, and I like it - it's clean and fast, if a bit grey. This is a 4K screen, and it's not applied any scaling by default - checking that out will be step 1 after installation.