Help! Only staying in Paris one night loosing sleep on where to stay?

If I were you, due to your time constraints, I would focus on what I really wanted to see, and stay in the vicinity so I wouldn't lose a lot of travel time, even thought the metro is super-efficient and gets you most anyplace you need to go. Rue Cler is charming, but if you're going to run right past it to get to the Louvre and the Orsay, why stay there? On the other hand, if you just want to do one specific thing out of your two days (e.g., spend 1/2 day at the Louvre and then enjoy wandering through Paris), staying in a cute place like Rue Cler or my favorite, the 5th arrondisement, gives you more time to "feel" Paris.

So - what do you want to do? That will help answer your own question.

Good sound advice! Here is our tentative itinerary:

Day 1
9:00am - Notre-Dame and Sainte-Chapelle.
11:30am - Metro to the Arc de Triomphe.
12:00pm - Walk down the Champs-Élysées and through the Jardins du Tuileries.
1:30pm - Tour the Louvre.
7:00pm - Dinner along the Seine.
8:00pm - Metro to the Trocadéro, and a stroll to La Tour Eiffel
9:00pm - Metro to the hotel overnight.

Day 2
The following day we're off to Disneyland Paris. We'll spend the entire day here and at Walt Disney Studios Park and the Disney Village. Later that evening, we board a night train for Barcelona.

Where would you stay?

If you don't want to be lugging bags around, here's a suggestion. Since you're arriving at 7 am, you'll be in downtown Paris before most things are open. Reserve a room at a hotel near the Gare Austerlitz, which is where you're leaving from, I believe....something like the Mercure Paris Austerlitz at 90 Euro/night (www.accorhotels.com). Go there directly, tell them you're checking in that day, and ask if you can leave your bags there. Head out and visit the sights. Then, when you check out the next morning, ask to leave your bags there again, and head out touring. When you're ready to catch the train, head back to the hotel, grab your bags, and walk the 200 meters or so to the train station. You'll want to make the best of your time, so the hotel is really only a place to crash for one night. As the earlier poster said, plan your day well so you don't lose any time back-tracking. Maybe start with Notre Dame, walk the Left Bank, cross over to visit the Louvre, and work out from there.

Why the "Metro to the Trocadéro"? Neither of the 2 subway lines that stop at Trocadero runs along the river. If you're going to the Louvre, and then having dinner near the river, then both Trocadero and the Eiffel Tower are just a short, pleasant walk from there.

Since this is will be your first time there, I must offer one piece of unsolicited advice: keep your itinerary flexible-- by the middle of Day 1 (if not earlier), you may change your mind about Day 2.

Norm, my husband really likes your suggestion to stay near Austerlitz and asking a hotel to store our bags the 2nd day. (that would be a smart decision given we will have 3 weeks worth of luggage with us) I like the "Hotel de Londres Eiffel" but it would require us to walk 4 blocks with luggage. Hmmm...

Mademoiselle Fifi, thank you very much for the clarification on Trocadero and the suggestion to walk there. We have changed our itinerary! I agree on keeping flexible on the 2nd day. (I wish we had more time in Paris, oh well next trip) My husband is a big Disney fan (we actually got married at Disney World) and per his words..."you didn't think I'd make it to within 20 miles of Monsieur Mickey without saying "Bonjour"?!

The rest of our 3 weeks looks like this: Barcelona, Palermo, Naples, Pompeii, Sorrento, Capri, Rome, Florence, Marseille, Nice, Monaco and Madrid.

Any more hotel / itinerary suggestions before I book one?

Oops, sorry-- having taken mostly longer, more leisurely trips where I stolled around week, everything SEEMED like a "short walk" to me; never realized that Eiffel Tower to the Louvre was almost as far as from the Arc to the Louvre, and you don't have time to waste.

Maybe a more efficient route would be to see the Louvre right after Notre Dame / Ste Chapelle area, then Tuileries, Concorde, etc. That will bring you close to Pont de l'Alma, where(if there's time) you can take a boat tour, or dine at a highly-recommended restaurant with a nice view (can't remember the name right now-- I can look it up later). After dinner, walk the Champs Elysees toward the arc, which is open until quite late and looks more magical by night anyway.

From the Arc, Metro 6 goes directly to Trocadero for the last part of your itinerary, and from Tour Eiffel you can take RER C to Gare d"Austerlitz if you're staying at the hotel mentioned in one of the posts above.

I would not stay in rue Cler - though I have stayed there twice. It is out of the way and peaceful, but you probably do not want this for a short stay. You will be spending a lot of time on the metro going to other places -- though it is very close to the Eiffel Tower and you definitely want to see this -- so it isn't a total loss! But I would stay as near to the Louvre and the Seine as you can. (though the idea to stay near the train station is good, if not the ideal location, because you want to minimize travel time to connecting train). But if you want atmosphere, do the Marias or Latin Qtr (particularly if you are young!)
I personally would skip the stroll down the Champs Elyses -- you don't need to wast time on unimaginitive stores, but see the arch de Triomphe if you can. There are much better stores in the Marais, and you will discover many wonderful places just by strolling around.

Follow Rick's recommendations for 1-2 days in Paris if he has this. Can't go wrong.

I agree with Betty.
I would skip the stroll.
concenetrate on the main sites and also just be flexible. Have on out line and be prepared that you may not be able to stick to it or see everything you want. I think starting at the Louvre or Notre Dame first would be a good idea, just based on the crowds alone.