Hi bro,
Rome is a beautiful place with a wonderful balance of historocal and the modern environment.
I would suggest the following things :
Take the opentour bus ticket vaild for 2 or 3 days. This is a nice way to look around (from the top open level of the double decker bus). THis takes you close to quite a few of the monuments. You can get on and get off as and when you please and as many times as you wish, take the next bus and continue.
Make sure that you visit the Colloseum and the Vatican and do take the group tour there. They are excellent tours and they explain all about the monuments. THey will give you a small earphone or a reciever and walk you through the tour.
Trevi fountain, spanish steps are also worth seeing once. (nothing great but hey why not look around).
We had booked the Grand Hotel Palantino in Rome, fantastic hotel, big rooms, great service and excellent location. Walking distance from the colloseum and next to a metro station.
Do also check out the local cuisine. One more thing, if you stay in the same hotel there is a supermarket on the opposite side of the road and an indian resturant (if u like ) opposite it. Pick up basic stuff from there as most things like coke n water are quite expensive outside.(learnt the hard way but you can save a lot here)
Paris --
One way to enjoy most monuments in Paris is take the L'Opentour bus. It costs about 25 euro for 24 hours and runs on 4-5 routes. THe major route that covers most monuments and takes 2 hours. THis is not a guided trip but a get on get off service so sit on top of the double decker bus and enjoy the ride. THen based on what one wants to see get off, visit the monument then hop back on.
What i did was cover the entire route once and then just got off on the second trip.
A cheap and wonderful way to look around.
Two main things, not to be missed are the Louvre and the Eiffel tower. Take the lift to the top of the Eiffel, its incredible. Missed seeing the Moulin Rouge and the Lido Show:( Surely something worth seeing if one is interested.Need to book in advance,
Take tips from the information desk at the CDG. You can also buy the opentour bus pass from there . Also if you want to go to more museums (the military museum is a suggestion, also check tripadvisor) take a museum pass, allows you to skip lines and is for 35 euro per head for 2 days. THis is also available at the information desk at the airport.
I would suggest not cramping too many things in Paris...just do what the heart feels.Roam around Champs Elysees, St Germain etc. .
Just take it all in at leisure. Isnt that the whole purpose ? Let me know if you need any info.
p.s The hotel rooms in Paris are really tiny so be prepared for that. We stayed at the Best Western Star Champs Elysees. Nice but very small rooms compared to other Best Westerns in other places. But then thats how Paris is.
Also visit tripadvisor once and go through the information available for both Paris and Rome. It will give you a lot of options of the things you can select.
Whew... hope this helps. Lemme know if there is anything i can suggest.
Cheers . Hope this helps