Getting back to hotels for a moment, I've just come back from Venice and stayed in Ca della Corte which was excellent, choice of rooms and small apartments, very friendly English-speaking woman called Annarosa.

See:

http://www.i-escape.com/cadellacorte.php

Canal side rooms tend to have more mozzies than garden facing rooms.

I agree with diva48, the plug-in repellant does work. Have been traveling with it ever since we lost precious sleep over the attack of the mosquitos. If you don't put it too close to where you sleep the smell isn't that noticeable. It definitely is a life saver. ;)

anitas,

We just returned last night from Italy and stayed at the Al Piave in Venice. I got eaten alive by the mosquitos and my husband never got a single bite! Just goes to show who's sweeter...
I bought the Autan, as was recommended on many web sites and it seemed to help somewhat. I agree with the poster that said they were tiny bites, though and went away quickly.
As for the Al Piave, there are no screens on the windows. I'm not sure if they have AC since we were there in October. We paid E140 with cash (they offer a cash discount) and thought the place a good value for Venice. It's certainly not a luxury place, but it was clean and the bed was comfy. I thought the owners and staff were very helpful. They made restaurant and tour reservations for us and gave us some good tips for places to eat. We liked the location because it is far enought from the noisy and crowded San Marco area, but is easy to walk most anywhere. It's on a quaint little street with some small shops,a laundramat,and near a small grocery store. No views to speak of though. The room was small, but it sounds like most rooms in that price range are tiny.

Deb

I've been to Venice only twice, both times in August, and don't remember seeing any mosquitos.

For a hotel recommendation I really like Pensione La Calcina (in the price range you mentioned, on the Guidecca canal). www.lacalcina.com

My wife and I stayed at the Wildner Hotel in late September. We left our third floor windows open during the day while we were out and never saw a mosquito. Perhaps some of the folks who have had problems stayed near canals in which the water doesn't move much... stagnant water is where mosquitoes breed. The Wildner is right on the lagoon and there is constant motion in the water there. Just a thought...