Italy to Seattle

Amsterdam is generally an easier place to transfer than either London or Paris. Either Florence or Rome airport are easy enough to get to by taxi for an early morning departure, but the Florence ride is shorter and cheaper (about 30 minutes, 25 euros). Florence airport is also smaller and therefore simpler than Rome/Da Vinci/Fiumicino. I see that Delta/KLM does offer the Florence-Amsterdam option, so if the price is right, I'd go for it.

FLR is actually only 15-20 min by taxi from the Florence city center (~3.5 to 4 miles away). It's one of the closest airports to downtown in Italy.

If you fly British Airways via London LHR, Florence wouldn't work, because BA doesn't fly from FLR to LHR (only to London City, LCY). But KLM has 3 or 4 daily flights to AMS from FLR.

We've flown this route a lot and prefer Amsterdam as the connecting airport - It's much more compact than Heathrow and easier to maneuver, imho.

I'd have to save a lot of money on the flight for me to choose a London transfer. I've always found Schiphol to be a pleasant experience.

I've got to agree with Chani. The security lines at Heathrow when you change planes are insane.

We are going from Vancouver (via CDG) to Florence next September on Air France if you want to check into that option.

mar,

Have you also considered transfers in Frankfurt? That's a route I use often and because it's a major hub there are usually lots of choices.