paris pass

NO .. do not buy Paris pass. First , lets make sure you understand the difference between a Paris Pass and a Paris Museum Pass. A Paris Pass is over priced and just never works out to worth it, it does include metro, but with only 2 days you may end up walking to alot of sights.
A Museum pass may work out,but only if you see at least two or three sights each day. For Notre Dame, the church is FREE, but the Towers are not, but the MP does cover the admission,BUT does not allow you to line skip there. You must arrive 1/2 hour before Towers open to avoid long waits. They only let 20 people up at once, so line moves slowly,,, very slowly. The church line will look scary long, but moves quickly, so see Towers first, then church. For other places you have named lines not an issue. For Louvre (you didn't mention) lines can be avoided by NOT using the Pyramid entrance, enter via Porte Des Lions , or through the underground shopping mall, Carosuel, which you access from Rue Du Rivoli. I have done this many times over the years, always in high seasons ( may -Sept)and have never waited more then 10 minutes to get through security( which the pass does not allow you to skip anyways) So, what you need to do is decide which site you are going to see and add up the admission costs.. it may or may not be an advantage to get the Museum Pass. For Versailles you can purchase a ticket online on their website or use pass. .lines for security there can be long regardless, get there early, before it opens, or late in day.

I agree with EVERYTHING Pat said - so read her advice carefully and follow it! To amplify: "the lines" are only an issue at a few places (Versailles is the main one). That's because either there is no line, or because everyone has to go through security, even if you skip the ticket buying line. And many sights are free (Sacre Coeur and Notre Dame, not including climbing their towers) or not included on the pass (Eiffel Tower). You should make a list of what you want to see, and see if it's covered on the Paris Museum Pass (here's the official website: http://en.parismuseumpass.com/ If it saves money, or if the numbers are close, then get it (and don't get in in advance from the US; it just costs more that way). But if it doesn't, just get advance tickets for Versailles, and then pay for other sights as you go. For transportation, buy a carnet (pronounced car-NAY) of 10 tickets. These are good on buses, the metro, and the funicular to Montmartre, and are sharable (so two people can use 5 each). When you run out, just get another carnet. In two days, depending on how much walking you do, or if you take some taxis to save time, you may not even use 1 carnet. On the other hand, if you know you'll be using a lot of transit, get a Mobilis. This is a day pass, and saves money if you're taking more than about 5 rides (I haven't checked the latest prices on these options, but someone else here will know).