They're all good; Shimano, SRAM, Campagnolo. So this is strictly a subjective statement: if it really is an Italian frame, go with Campy. The fact that you've asked twice in the thread about where stuff is made means you're thinking about it enough for it to mean something to you. Sounds like you'll be happiest if you put Italian parts on your Italian frame.

The one and only Italian bike I've ever owned ('97 Pinarello Vuelta) was equipped with Shimano 600 when I first saw it. I traded for the bike, and knew immediately that despite the fact that the Shimano 600 parts were nice, I had no interest in keeping them on the bike. Again, it was strictly subjective, but this was a special bike to me. The deal I eventually ended up making didn't even include the Shimano parts, I just wanted the frame and fork. I put Campy on the bike, and I'm very glad I did.