Just a quick post having returned from Umbria (thank's for the recs.)
1) Can heartily recommend Il Postale in Citta di Castello - very classy food with the most expensive tasting menu being E55.
2) Orvieto is a fantastic town. Several people have posted restaurant recommendations but it is also full of deli's/wine shops. Generally I found these too boutiquey with the glorious exception of the small delicatessan at No.11 Via de la Duomo (runs between Cassa(sp ?)Cavour and the main square with the basilica).
On the subject of which, this part of Italy also enables you sample the glories of european street naming:
- France specialises in naming streets after unknown local dignitaries (Rue Henri Bertillon...who he, Ed ?)
- A mediterrainian speciality (extending into North Africa and the Middle East)is obscure dates (C.25 October - what happened then ?)
- But this area of Italy is kindly predictable for its many overseas visitors. Whatever you are looking for will be along Cavour St, across from Christopher Columbus, next to Garribaldi and just off the Via de Unita D'Italia.
America, is just dull and numerical and for a full description of the willful obtuseness of British streetnaming, please see the George Mikes book "How to be an Alien".