We just returned from our first trip to Paris and although it is crowded, it felt magical to us. Perfect spring weather after an interminable New England winter was a big part of it. I think, though, that a big part of what made it great was following the advice in the RS Paris guide about timing. If he said, "don't go on Tuesday," we went on Wednesday. If he said, "the crowds thin out in the afternoon," they did. We followed the suggestion to see the Trianon palaces first, enjoy the grounds of Versailles and see the palace in the late afternoon and we never stood in a line.
I think it would be possible to have Paris feel like one big cattle call. But it is also possible to have it feel like one discovery after another. We did a short walking tour with City Insiders Paris which I liked very much and thought was an excellent value.