Hi

You only have 10 days so forget Naples and Milan. So 3 days Rome, then bus to Siena (2 nights), bus to Florence (2 nights) and train to Venice (3 nights). You won't need a car. We are in currently in Venice after doing this itinenary and and it worked well. Is it better to fly to Paris from Venice i.e quicker/cheaper?

I agree with worldinabag. The places you list are too far apart to all be visited and enjoyed in ten days. Unless you are just checking stuff off a list, not really seeing anything. I would think heading south to north makes more sense, because you are then closer to Paris.

Do not rent a car. You cannot use it in the main cities because of traffic restrictions, very high parking fees, and difficulty in finding your way around. The only place would be in Siena if you were going to take day trips in the countryside, but you will not have time to do that.

we flew on Easyjet from Venice to Paris. Cheap and quick. Have a great time!

Yes with 10 days pick 2, 3 places MAX or you will spend more time in transit than you will actually seeing and experiencing the places you are visiting! For me that would be Venice, florence, and Rome.

What time of year are you traveling? I agree that you don't have time for all you listed in 10 days. You can either depart by Easy Jet from Venice or Rome to Paris (forget Milan/Naples this trip). Time of year might affect whether you want to go north to south or vice versa.

We will be in Italy from September 15th to 26/27. I think we will prefer going south to north because our next destination is Paris. I think3 days Rome, then bus to Siena (2 nights), bus to Florence (2 nights) and train to Venice (3 nights) sounds about right.
What I am wondering is whether Siena is worth doing or should be raher spend more time in Rome and Florence ?

I'm with the rest....no more than 3 destinations. For a 2 night stay you only have 1 full day in that location!! For my two cents, if you must have 3 locations, make it 4 nights Rome, 3 in Florence and 3 in Venice. If you insist on Siena make it a day trip from Florence - an easy bus trip and no extra packing and unpacking. For a more relaxing trip I'd say split the nights and make it 5 in Rome and 5 your choice. You're traveling for two months - slow down a little and take time to enjoy your surroundings!

Have a great trip