I just got back and will give a recap on the commute to/from CDG. When we arrived, I admit being very "green" and new to Paris I took a cab to the hotel. We hooked up with another couple that flew in from FL and the four of us got a cab for 300 francs. It was hard to get a cab to take four people. The meter said 218 francs but somehow we had to pay 300. That was the last cab we took. The metro/train system is awsome and easy to get anywhere for 8 francs. We bought a 10 ticket for 55 francs to last the long weekend. On the way home we took a metro to an RER for 48 francs each directly to the airport in about an hour. If you have more bags than you can carry up and down stairs easily do not take the trains. One side note on the trains, get a train/metro map and in about 5 seconds you can get anywhere. Just follow color/numbers and always look at the map to see the final destination for your line/direction. Once in the station just follow the signs to that line and direction.