I've always felt like the euro banknotes are kind of bland compared to currecies such as USD or GBP. There has been a proposal to put some people on it, but the selection seems aimed more at the impossible goal of satisfying everyone than at historical importance to the EU project. I know my selection would not get approved for that reason, but I would suggest:
€5 – Richard von Coudenhove-Kalergi
€10 – Altiero Spinelli
€20 – John Paul II
€50 – Konrad Adenauer
€100 – Robert Schuman
€200 and €500 – abolished altogether