Your best bet is both 900/1800. There ARE quad bands. IMO you would be better off with the 900 rather than 1800. TIM uses both, but I don't know WHERE. Our Italian friends probably have more info on Sicily.
1900 and 850 are useless in Europe; those or N American frequemcies.
I can think of any # of good tribands for USA - Nokia 6610 (got one - actually, I had a total of 3 of these and replaced them with
, Moto V-300 (got one), Moto V-330 (got one). The Moto V-188 is a quand band and my son has one. Those are just a few you could by. I have had a Moto P280 which was a solid phone - a bit old, of course, by now.
Stan