With due respect to PSU Lion, I would strongly caution against the CDG Hilton. Using public transportation, it's a long ride from Paris (at least 45 mins, and 60 mins or more from La Defense) and it's on the suburban train (RER) line, which has been growing increasingly unsafe, especially at night. The situation has grown so bad that the RATP (who operate the RER trains) recently decided to close off all but the front cars of the trains in the late evening, so that riders would not be less isolated and susceptible to thefts/assaults.