Whit85---you've already ruled out my favorite country, but if I were you I'd go back to Paris for a couple of days then go south (Cannes) or to Normandy. It'll be fun for you to show your husband what you remember of Paris and see some new things, too.

I would go to Prague as it's so different from Italy. You could combine it with Vienna or take day trips from Prague. 7 days is a bit too much for Prague.

I would want to avoid the heat in Spain or southern France.

In August, I might head to Ireland. If you plan to have kids, Ireland is so much better seen by driving that it might be tougher to do with young kids (potentially with low tolerance for driving!) than, say, London or Paris, so this might be a good time to do it.

If you do Ireland, just don't try to cram too much in. Ireland is deceptively small - it takes awhile to get around. A week would give you a good amount of time in the west or southwest, for example, but tough to add Dublin or Northern Ireland as well.

@dwdvagamund -- What's your favorite country? I really haven't ruled anything out yet; the countries I named are just the current front-runners. But I agree that it would be fun to go back to Paris and show my husband what I remember of France.

Hard to say not knowing a few things such as what kind of things you like to do and mode of transport preferred between the two locations. Would you be flying into one city and out of another or booking a roundtrip to/from a gateway city?

That aside, here are a few pairings (and all are fine for 30 year olds w/o kids):

London & Paris
Dublin & Copenhagen or Stockholm
Berlin & Ibiza
Marseille & Lisbon
Barcelona & Basel
Prague & Istanbul
Amsterdam & Lyon
Edinburgh or Glasgow & Bruges

We went to Prague with a day trip to Cesky Krumlov and then by train to Vienna last summer and thoroughly enjoyed the trip. But, that said, London is my very favorite place to go; and if you want to, there is a wide choice of day trips from there.

My vote would be London and Paris - world class cities that offer very different experience. Easy to get between by booking www.eurostar.com 120 days out to get the cheapest price.

I recommend booking an open jaw flight, into your first destination and out of your second to save time and money backtracking.

Enjoy!

Thanks so much for all your thoughtful recommendations! I love hearing all of your perspectives.

bluestar -- Those pairings are all very helpful. Marseille is an interesting option. When I studied in Paris, the Parisian family I lived with said it wasn't worthwhile to go there (though they also said the same thing about London and England generally, so I knew they were a little biased). Because of that, I never paid much attention to Marseille but after doing a little research, it looks like a place we would be interested in, if not on this trip, then sometime in the future. Our interests are fairly broad -- we like a mixture of museums/historical places with just relaxing and enjoying the culture. Since we haven't planned anything yet, transportation is wide open, and we'll do whatever is most convenient. The only things we're not wanting are 1) a beach vacation and 2) anything too action-packed since our last vacations were the Florida Keys (beach) and Whistler, B.C. (hiking, white water rafting etc. )

jent103 -- That is just the kind of advice I'm looking for because we do want to have kids in the next couple of years. Also, my husband is 100% Irish, so that's one of the places he's most interested in.

Thanks again, everyone!

I too would vote for London and Paris. ... For the exact reasons mentioned above... And if you think you will have time, energy, money and days left.... Hop the TGV to the south of France and fly home from there. To me, that is about as close to heaven as you can get...

If you should decide to head south to Provence, you'll need to secure hotel bookings ASAP. That's prime high season.

Ok, it looks like London and Paris are the winners! After doing more research and spending hours in the Barnes & Noble travel guide section, I really fell in love with the idea of Provence and the Cote d'Azur. But after pricing it out, I found that it would cost significantly more, which makes sense now that I know it's high season there (thanks Underhill!). So that will have to be a future trip. I want to work in some day trips from Paris, so I'll probably be posting my tentative itinerary for feedback soon.

Thanks again for all your comments!

The Romantic Road in Germany is a gorgeous drive if you like seeing the countryside. Fly into Munich and you could probably see some of Switzerland as well. Venice is definitely unique.

Whit85--

Italy. However, in your case, I'd say Paris and Northern France, as you've now chosen, is the better choice. Even we don't go to Italy every time we go to Europe (UK this year.)

Are you also going to London? There are lots of places in Northern France and Belgium to see, and all are easy drives from Paris.