We wre in Paris in April 2012.

We used the Metro extensively. We purchased a book of 10 tickets (one ticket, one trip) that was discounted over buying the ten trips individually. This worked well for us. No photo needed. Just buy the tickets at the Metro booth. When you need more, but 10 more. They have a name, but I cannot remember what it was. The person in the booth will know.

I was looking at things online and there are 2-day, 4-day and 6-day passes but not knowing how often we'll need the tickets, I was unsure about buying. I like your plan of buying 10 at a time--that seems much more reasonable. Thank you traveldawg!

The carte orange has been replaced by an electronic card that is basically the same, it is called Navigo (Navigo Decouverte for non-residents). I think it costs 5 euro for the card, aside from paying for the week's transportation on it. Yes, you ned an ID photo to get it because it is strictly personal (for the person's ID on it). It is for one week starting on MOnday, though, so depending on your dates, that may not be the best for you.

You cannot buy Paris metro tickets or passes in other countries. It costs around 20 euro, you could well not need it and just use individual tickets as mentioned above (cheaper if you buy in a packet of 10). But if that week's time is good for you, it would make sense to buy it.

The word traveldawg is looking for is a "carnet", which is just the pack of 10 tickets.

egwright, the passes you are talking about are the tourist passes, not the same thing as either the carte orange or the reincarnation. You can buy the tourist passes elsewhere (although why you would, I can't imagine) as they are not date encoded, they start when you first use them.

What day of the week will you arrive and what day of the week will you leave?

The Navigo runs Monday a.m. to Sunday p.m., so purchasing in the middle of the week costs the same and gets you less use. If you arrive on a Saturday or Sunday, you might by a carnet of 10 to get you through the weekend, then have your Navigo filled on Monday morning (if you'll be there the rest of the week). You only purchase the card itself once, and you refill it whenever you need it (on subsequent trips).

You are staying in a very central area so, depending on how cold/wet/snowy the weather you may do more walking than you think. You can easily walk to the Louvre, Mairais area, Hotel deVille (which in December and January has a little skating rink, carousel and dessert trucks with amazingly good chocolate covered marshmellows), St. Germain, Notre Dame, Eiffel Tower, Bastille... you'll need to take transportation to Montmartre and out to Versaille, of course.

If you saved the extra passport pictures, just take them to put on the Navigo. Or take a few close-ups with your digital, print them off and take them.

I love Paris at Christmas and New Years. Look for the vin chaud being sold out the windows of some cafes. Have a wonderful trip!

egwright, the 2-, 4-, and 6-day passes are for museums. They have nothing to do with transportation (though the truly silly Paris Pass thingie gives you some sort of transportation options - but it's a terrible deal, so don't even consider that).

And except possibly for the online discount you can get for the Vedettes du Pont Neuf boat ride, there really isn't much point in buying stuff ahead of time, especially when it costs more (and of course you can buy tickets for any sort of public transportation in Paris - or anywhere else, for that matter - in a different country).

Just get the carnet unless you happen to be arriving on a Monday; then the Navigo might be useful. You can use métro tickets on the buses as well.

Forgot to mention, the Navigo is also good for riding the public bus system.

You have to use the Navigo Découverte. at least 3 times a day to break even [as compared to the carnet of tickets]. They make the most sense if you are going to be in Paris Monday to Sunday. The less days in that given week, the more you have to use it to break even AND you will still need carnet for the days not covered by Navigo.

Helpful Metro tools:
http://www.ratp.fr/en/ratp/c_5000/accueil/
www.parisbytrain.com

In one tiny exception to the info posted above, carnets are (or were, two years ago) sold in another country, inside the EuroStar terminus at St-Pancras, London. But if memory serves, they were more expensive there than after dismounting at Gare du Nord.

Thanks Everyone!

In my previous post I asked what day of the week you will arrive and what day of the week you will leave. The reason for asking is that on Saturdays and Sundays your children will each be able to buy zone 1-3 Ticket Jeunes passes for each weekend day. The pass is for persons under 26 and costs €3.55/day. On the rest of your days in Paris they can share carnet tickets with you and your husband.

If you haven't already found this, you might find it useful:
http://goparis.about.com/od/transportation/ss/Metro_and_Buses.htm

I find this lady's voice irritating (and don't copy her French pronunciation), but it does show the basics on how to use the system:
http://www.youtube.com/watch?v=Q6ACxAAzizY

Also I urge you to use buses, not just the Metro. There are booklets that give you the routes, and it is much more interesting to see things and it may get you closer to your destination. Some of the bus lines are really excellent just for "sightseeing" purposes also, passing by major sites.