KDE. It's customizable without adding lots of weirdness. It's got a solid set of included tools like Dolphin and Konsole. It's generally very stable and visually attractive.

No shade to other DEs. I've tried lots of them, I even have a couple of alternative DEs I'll log into when they are useful (i3 is great if I am doing something repetitive). But KDE is just the most comfortable for me for daily use.

The non-Gnome COSMIC DE that System76 has been developing is looking really promising though. I have the alpha on a spare laptop and find it very functional.