OK, many of the suburbs are pretty awful, but Paris itself is architecturally magnificent. Contrary to popular belief, I find Parisians very friendly, and for art and history it is almost unbeatable (London and New York are tough competitors).
My favourite part of Paris is when you cross the Seine southbound on Line 6 (Ch. De Gaulle Etoile to Nation). You come out from under the ground and you immediately see the Eiffel Tower on your left. Knockout.
P.S. I was taking to man and his wife in our local pub some time ago. They said they had just come back from Paris and Euro Disney. I asked them what they thought of the architecture. Fabulous they said, to which I replied that is was all designed by a Berliner called Baron Haussman.
"A baron really built Euro Disney?" asked the husband.