Don't know when you're going, and so this might be a bit out of your price range, but no so much as to rule it out. The only place I will ever stay in Venice is the Locanda Orseolo. The cheapest Double Standard is EU120 in low season, and the most expensive Double De Luxe is EU300 in High season -that's the range. See:

http://www.locandaorseolo.com/en/

and trip advisor reviews (610 of them!!) at:

http://www.tripadvisor.com/Hotel_Rev...ce_Veneto.html

For Florence, we like the Pensione Bencista, which is actually "up the hill" in Fiesole, but right on the very convenient number 7 bus line. It is very basic, but the people are lovely and they have million dollar views from the terrace.
It is right in your price range, actually on the low end if you go with the "bed and breakfast rate" or "half board" which is breakfast and dinner (dinner gets boring) there is no need for the full board since you won't be there for lunch in any case. Take the money you save here and splurge on the Orseolo in Venice.

The web site is:

http://www.bencista.com/main.php

and the pictures give a true representation. Do check out the dogs on the "outside" page of pictures, they will usually be sunning themselves on the front steps and you'll need to climb over them to get into the lobby.

The trip advior reviews at:

http://www.tripadvisor.com/ShowUserR...e_Tuscany.html

are pretty much spot on and tell both the good and the not quite so good. We love it, but others aren't quite as taken.

If you really want to stay in town, I recommend the Relais Cavalcanti. The web site is:

http://www.relaiscavalcanti.com/english/index.htm

and trip advisor reviews can be found at:

http://www.tripadvisor.com/Hotel_Rev...e_Tuscany.html

Nice people, clean and spacious rooms, in the middle of everything.

For Rome, we liked the Relais Banchi Vecchi. It was a bit unusual, and we never saw any of the staff after the first day – ever – but it was one of the nicer rooms we’ve had, clean, large, GREAT bathroom and the location is exceptional. The web site is:

http://www.banchivecchi115.com/inglese/index.html

The room in the picture with the red bedspread is the one we had.

And trip advisor reviews can be found at:

http://rome-hotels.tripadvisor.com/H...ome_Lazio.html