Forgot to mention this is for LATE MARCH. Thx!

London will be your quickest flight to Europe from DC. You can probably non stop and arrive with less jet lag and be ready to see the city.

Choose one city with a direct flight from BWI or Dulles and stay there the entire time. London or Paris are great ideas but a bit chilly in March. From the east coast though, I would do Venice! Love that place! And March weather is agreeable.

Don't worry about jet lag. Going you'll be all amp'd up anyway and coming back it'll wear off at home so who cares. Have a great anniv trip!

The cities you mentioned are lovely and romantic, but the end of MarcH may not be the best time of the year.
Someplace warmer like Rome or Barcelona ?

March 31 is Easter so I would avoid Rome for the crowds and probably higher hotel costs.
I just wouldn't fly so far or change planes for a four night trip. You lose so much time traveling!

If you don't mind the cold, Montreal or Quebec would have the french flair and history and good food. You could also stay in the US, just fly south or west to get warmer cities. Just a thought!

Montreal is a big city without much flare IMO...
, bur Quebec city is small and romantic...could be cold though

flair

Thanks, everyone. We want to go somewhere we've never been. So London, Paris, Italy (and Montreal and Quebec) are out. Barcelona is a possibility, though I'm much more interested in Amsterdam, Prague or maybe Vienna.

Does anyone think Buenos Aires is a good idea?

It seems crazy to me that you would travel that far for 96 hours, but I guess that is the world we live in now days. Can you really enjoy a big city in that amount of time? Personally, I would head to someplace like San Francisco, Portland, Oregon or Vancouver, BC. Frankly, I would probably just stay near DC and go to a nice hotel there.

I agree, that seems a bit crazy to fly that far for 4 days, but I do think Buenos Aires is a great city. We were there in March and the weather is ideal - it is their fall. Food is fabulous there and cheap. However, I personally would not rate Buenos Aires above any European city I've been to.
Here is a link to my trip report for Buenos Aires along with a lot of pictures:
http://www.fromhometoroam.com/2012/07/buenos-aires/.

I've been to Buenos Aires and it was not my cup of tea. I think I would be especially uninterested as an anniversary trip. Have you any interest in Rio? I prefer Brasilian food. Or Chile? Great food, great wine. Pretty vistas.

Part of your jet lag problem, especially in March in the far north of Europe, will be the more limited hours of sunlight. You also run a very high chance of getting wet, wet, chilly weather in places like London and Amsterdam.

For an anniversay, I might like someplace like Costa Rica or Belize rather than a super-city getaway. Just so long as I wasn't in the places where people do "ziplines" and that stuff. Someplace like an ecological reserve, with a tree house.

The New York Times has this regular feature of "36 hours in _________". You might get some ideas browsing through their archives.

http://topics.nytimes.com/topics/features/travel/columns/36_hours/index.html

brook, Buenos Aires is a terrific idea. And March is September south of the equator.

< By the way, we love gorgeous cities, great museums, great food, luxury hotels, interesting sights.>
Buenos Aires has all of that.

gorgeous city,a little tattered gorgeous, Paris of South America.They had an economic collapse in 2001, I was there in 2007, so it was still recovering, sort of both areas of decline and areas of prosperity.

great museums, actually good art museums, small Evita museum.

great food-Our favorite steakhouse-La Cabrera in Palermo neighborhood. Our favorite Italian-Sottovoce (Libertador) in Recoleta.
Cafes-Tortoni, La Biela

luxury hotels-Recoleta neighborhood is the place to stay- $$$$ Alvear Palace, Park Hyatt, Four Seasons.
We stayed at $$ Melia Recoleta Plaza Boutique Hotel, 1 block from the Alvear Palace.

interesting sights- the best activity is walking the neighborhoods-Microcenter & Plaza De Mayo, Puerto Madero, Congresso & Avenida Corrientes, San Telmo on Sunday- flea market day, La Boca (guided tour only), Retiro, Recoleta & Barrio Norte, and Palermo. Don't laugh if I tell you BAs most famous site is the Recoleta cemetery.
What we did was take a private tour(driver + guide) of the neighborhoods- with several stops(cemetery,La Boca, cafe Tortino, Plazas,Opera house, parks, on our first day. This was arranged by BA travel agent Cintia Stella who owns agency Wow! Argentina. She also arranged limo trans to/from airport, hotel, Tango show(Meh) etc. We also had her arrange our entire itinerary for visiting the whole country.I highly recommend an overall private tour and using lonely planet walking tours(modified or combined by you). Cabs were very cheap.

I have been to Amsterdam, Prague, and Vienna which are all worth visiting, but I think BA was even better,well at least equal.

The jet lag avoidance seems like a big plus. Go business or 1st class which helps with the flight. I live in Los Angeles so your travel would be a cakewalk to me.We flew LA-Dallas-BA(14 hrs), returned Rio-Miami-LA(18 hrs). Time difference 4 hrs?

Gary

BA is always described as the "Paris of SA" in other words, ersatz. It's where one goes after seeing all of Europe. Plus the flight is too long for the amount of time you'd stay. I vote for Vienna. It's romantic and has fabulous museums.

We've been to all of the cities you mention. I wouldn't spend 10 hours on a plane to go to BA. We found it OK but just OK - not in any way beautiful city.

If you haven't been to Amsterdam, it has nice museums and is a good place to visit for 3 or 4 days although I haven't been in late March. It would be easy to get there despite the probability that you would suffer a bit of jet lag.

As someone said, late March in the cities you mentioned
could be wet and cold for strolling around.
Amsterdam and Vienna have better museum than Prague.
None is known for fabulous food.
All are lovely and romantic.
I would pick one with the shortest, direct flight.

Several years ago I asked this same question. Ended up going to Prague for 4 nights, had a fantastic time.

I went in late November, and I remember it being pretty cold at times. But I think Prague in winter is beautiful, with the benefit of lighter crowds than other times I had Kafka and trudging through the snow to get to the castle going on in my head the whole time, which added to the experience

http://www.fodors.com/community/europe/3-nights-in-europe-from-the-us.cfm

Thanks, everyone, for some great advice. I think we're going to be able to do 5 nights now! Suddenly Amsterdam is looking better, I think. Is late March a terrible time to go to there?

Europe, of course!! You will never find such a romantic places as in Chezh Republic!

>>Suddenly Amsterdam is looking better, I think. Is late March a terrible time to go to there?<<

The clocks will switch in late March, so days will be a little longer. Amsterdam has a real spring, so you've got to be mentally prepared for maybe 5 whole days of constant drizzle, or even chill winds and a few downpours. Or it could pleasantly brisk with sunshine.

http://www.amsterdamlogue.com/march-in-amsterdam.html

Since you've now got five days and you love great food, think about taking the one-hour fast train to Antwerp and having some really great food, plus taking in the sights. Go early in the morning for a waffle, have a great lunch at a special restaurant, hang around long enough to sample chocolates and drink beer. They eat dinner early enough in Antwerp that you could even think of staying for a jenever cocktail and supper and be back in Amsterdam by 11pm if the train schedule works.