Will your return flight be from Rome?

Yes...

Or we could do the reverse, and fly into Rome - out of Paris...

With 9 or 10 days I would either visit Paris or Italy or Paris/Rome or Paris/Florence (Tuscany).

Will you be renting a car in Italy? If not you'll find the best public transportation from Florence and Florence will give you more cafes/night life than small towns. You'll really only have 1.5 days in Tuscany (half a day in Florence and 1 day some place else) so you'd do better keeping a central location and Florence affords easy access to Rome.

Don't forget to count the travel time between Paris and Florence and Florence and Rome. 10 days will become 9 days; 9 days will become 8 days.

Agree with adrienne....we just spent 9 nights in rome (with a few day trips) alone and we still didn't get to everything!

Sounds like a fun trip! Both Paris and Italy are wonderful places to visit.

A few (really few) of my personal highlights from trips to the areas you mentioned are:
- Tuscany: Montalcino, Montepulciano (We stayed with a lovely old lady that spoke no english but hosted us at her beautiful house overlooking the town and surrounding areas), Siena, st gemigniano,...
Definitely recommend renting a car just for the drive from Florence to Rome, so many little villages and charming spots to visit... But no need for the car in the cities themselves - they'd only be a huge hassle.
PS driving in Italy can be a bit confusing - their arrows on road signs are sometimes different than what you'd find in other places - for example instead of pointing up to indicate "go straight towards XYZ", they would point left towards the road , to indicate "yes, this is the road to XYZ"...
- Rome: Vatican city, the Roman Forum and around (expect long lines at some of the biggest attractions - so prepare ahead and see if there are ways to bypass the line through a tour or pre-buying tickets)
Finally - try the italian gelato any chance you can - it's the best in the world!
- Paris: The Catacombs - In the 18th century, Paris transferred millions (!) of skulls, bones, etc. from their overflowing graveyards to these abandoned stone mines. Today it's a unique and haunting experience walking through these underground caverns.
The louvre - You can spend days in this museum, one of my favorites in the world. The ground floor has amazing antiquities from the near east and egypt, and Islamic art is also a wonderful section. Oh, there's also the mona lisa but that's quite underwhelming and you need to stand in a long, long line... PS you can pre-buy tickets to skip the lines here too
The Sainte-Chapelle - A beautiful cathedral with stained glass windows. Long lines if you don't arrive early, but you can pre-buy tickets or get the joint tickets from the conciergerie next door first, and then you can skip the line.
Eiffel tower - skip the tower itself unless you want to stand in line for hours.. instead have a picnic in the park next to it, or admire the view from the Trocadero terrace across from it.

Also check out the paris pass to skip lines and get into multiple museums with this joint ticket.

If you have 9-10 days, that probably means one weekend or two- it may be worthwhile to decide on your direction (Paris-Rome or Rome-Paris) based on where you want to spend your weekend based on nightlife, restaurants or attractions. Some of the best restaurants in Paris often close for the weekend, not sure about Rome. Also some of Paris' museums are closed on Mondays, so plan accordingly.

Finally - might be worth checking online what festivals / holidays / events are around your areas during your travel dates. It's always fun to find something cool that brings together a lot of people!

HTH

Thanks everyone! I think we have actually decided to do an Amsterdam-Brugge-Paris trip this time..utulizing the train system. We will experience Italy by itself at another time.
Our tentative itinerary will be 3 nights in Amsterdam, 2 nights in Brugge, and 4 nights in Paris (perhaps cutting down to 1 night in Brugge)

That sounds like a good plan. And I would be tempted to add that extra day to Paris.

If you coming on an overnight flight from the US (PA?), you will be jetlagged and sleepy for the first day or so. Take that into account for Amsterdam.

We absolutely loved Brugge this past October and would not limit to one night. You could use it as a base for trips to Brussels and Ghent and eliminate Amsterdam this trip. Three days in Paris is better than no days but not nearly enough to enjoy the city.

If I was your age, I would skip Brugge and do more time in Paris.

Amsterdam is a wonderful city to visit, as is Paris (obviously). We once took the train from Paris to Amsterdam, and it was a good way to get there.

I also suggest at least 3 nights in Amsterdam, 1 night in Brugge (or add this night to Amsterdam), and 5 nights in Paris.

Sounds like fun!

Thanks all! I'm getting mixed feedback on stopping in Brugge/Brussells between Amsterdam and Paris. I certainly don't want to stretch myself too thin, but I would also like to experience as much as I can.

Tentative itinerary is:
Fri May 10th - 6:40pm flight from PHL
Sat May 11th - 8:40am arrive in Amsterdam
Sat May 11th through Tue May 14th - Amsterdam (3 nights)
Tue May 14th - train from Amsterdam to Brugges, Belgium
Tue May 14th through Wed May 15th - Brugge, Belgium (1 night)
Wed May 15th - train from Brugge, Belgium to Paris
Wed May 15th through Sun May 19th - Paris (4 nights)
Sun May 19th - 11:30am flight from Paris
Sun May 19th - 2:00pm arrive at PHL

Should we scrap Brugge and add the night to Paris?? Or is it a nice break between the 2 cities?

Brugge (Flemish) or Bruges (French) is an adorable little town with a bit to see; Amsterdam and Paris are beautiful cities with a lot to see. But all very much worth seeing.

I found Amsterdam to be a peaceful, quiet city - but then, I'm in my 40s and spent most of my time in the museums and wandering the Jordaan and those areas. You may spend your time differently, and find Amsterdam not so peaceful! So whether you need / want a break in a smaller, quieter place between Paris and Amsterdam kind of depends. Also, Brugge is FULL of tourists most of the time, so you won't get a break from that.

Whether or not you drop Brugge depends on your interests. Also, look at your travel times. To get to Brugge, you'll take the train to Brussels (a city that I really love, BTW), then take a different train for a 45-min. (I think) ride to Brugge. From Brugge the next morning, there is a train that goes from Brugge to Lille and then on to Paris, but when we traveled Brugge to Paris, it worked better into our schedule to take the train back to Brussels, then take the Thalys on to Paris. So factor in how you want to spend that travel time.

And if you decide to go to Brugge, if you haven't already, you must watch the movie "In Bruges."

I am not a fan of one-night stays. Amsterdam and Paris are two very different cities, so I think you don't really need Bruges in between them. We stayed 5 nights in Amsterdam and loved it. Very young vibe, but not overshadowed by cannabis.

I suggest 3 nights Amsterdam and 5 nights Paris.