Sorry to hijack with the first reply, but I'd recommend *not* doing Venice if you're only doing one city in Italy. It's the Disney World of Italy in my opinion. If you're going to do a longer trip, then I'd say to do Venice for sure - it is unique, but very, very much geared to the touristy thing.
I've never done southern Italy, at least no farther than a couple of trips to Rome, so my recommendations run to northern areas of the country. If you're going to do a short trip, go to either Florence, or even better, Siena. Wonderful old cities, great buildings, great people, great food, great art, and a true Italian experience. If you enjoyed Brugge, you'll love Siena for many of the same reasons.
Venice is kind of a one-trick pony. The canals and layout of the city are unique, but you don't truly get to experience Italian life unless you sneak off to the really back-alley areas of the city where the locals live. Otherwise the restaurants, shops, and stores all cater to tourists and, in my opinion, are nowhere near as good as in other areas of the country.
Actually, Bologna is a pretty neat city and it has good airline connections as well. Modena, home of Ferrari, isn't too far away, but it's almost impossible to get a factory tour (I have a good friend who heads up the publications department for Ferrari, and I still couldn't get in
. Did get to see Michael Schumaker do some hot laps at the test track, though
).
Still, Siena is at the top of my must-visit list.
[/hijack]
Sorry I can't help much with the airline thing. I've mostly done NWA/KLM 'cause of the frequent flyer upgrade thing. I'd try Alitalia, though. The few times I've been on them they've been O.K., and you might be able to get some direct flights from the U.S.
<whisper: go to Siena>