Woah, I just realized that co-incidentally there are 20 options in this list (a nice even number) so you are going to be voting for exactly 1/4 of them!
All of these people have produced at least two U2 tracks. Rick Rubin not included because although he produced Windows In The Skies, 'The Saints Are Coming' was a cover.
Mike Hedges produced the revised best of 1990-2000 versions of Discotheque, Staring At The Sun, Gone and Numb.
Nellee Hooper produced Hold Me Thrill Me Kiss Me, If You Wear That Velvet Dress, Sometimes You Can't Make It.
William Orbit did Electrical Storm and The Hand's That Built America.
I'd say the rest you guys probably know well enough.. if not go to YouTube type U2+their name+topic and the official audio of all the tracks they produce will appear with the song credits under 'show more'.