I dissent.

One of the joys of staying in Paris is walking outside your hotel and enjoying the streets of Paris: their atmosphere, their people, their shops. You can't do that if you're staying in La Defense. For that matter, it seems to me that the Champs-Elysees (Marriot's location) is one of the least desirable in Paris: instead of being in a neighborhood that teems of Parisian life, you're among fast-food shops and tourists.

There are lots of nice places to stay in Paris at all price ranges in neighborhoods that have atmosphere: St Germain des Pres, the Marais, the Opera-Madeleine, Montmartre, Bastille-Republique, Montparnasse. Sorry, but to me staying in La Defense (or the Champs-Elysees) is completely missing the point of it all.