Glad to see you made it from the dark side in tact
I'm not going to tell you what to use, just tell you my experience and you can take it from there.
My move from Window$ started with Meppis (Debian based/KDE) then to Kubuntu (Debian/KDE), then onto Mint (Ubuntu/Debian based /Cinnamon/Mate/Gnome3) then to xUbuntu which is where I am now.
I found the KDE envirnments a little hungry. I am on low powered hardware though.
Mint was/is polished, but didn't quite have the community size, and hence the add-ons that i would've liked. (This will change)
The XFCE desktop environments are, IMHO, the best place to start. They'll give a responsive and small desktop footprint with plenty of configurable options.
My next try is going to be Mint XFCE maybe?
The xUbuntu install is going swimingly well and is now totally integrated into the Window$ work environment I'm in.
Good luck! wish you well.