Actually, it may not be U2 but Bono's performance with Band Aid 20 tops the bill.
His voice of the iconic line had the confidence of a successful musician with the tone and phrasing that brings shades of the HTDAAB era. He truly improved on the original version where he sounded like a screaming girl who was trying so hard to be recognized but ended up sticking out like a sore thumb.
But for pure U2 goodness (and not just Bono), we have Christmas Baby Please Come Home.
Cheers,
J