Which if these three do you think is better suited to a first time visitor/tourist to New York City, staying 3 nights the weekend before Christmas?

new york

Not having stayed at any since I live here, I would still vote Peninsula. I've stayed at Peninsula in Chicago, and several Ritz Carltons, and I think Peninsula is wonderful. Also, can't beat the location (5th Ave and 51 st), right near Rockefeller Center, 5th Avenue stores like Saks, St. Patrick's, etc. Christmas time is a magical time to be on 5th Avenue and near Rockefeller Center, where you can see the tree, skating, etc.
As for Ritz, you didn't specify, but if you choose it go with the one on Central Park South, rather than by Battery Park, which is a bit more out of the way, especially for a first time visitor.

Thanks for that, would you say that the Ritz / Central Park is well situated too for someone like me....who has EVERYTHING to learn about NYC!!

Ritz Carlton is on Central Park South, near the Plaza hotel and the beginning of Central Park. Central Park South is the equivalent of 59th Street, so it is a few more blocks from Rockefeller Center, etc. but definitely not "out of the way." It is a lovely area.
Like I said, I've stayed at several Ritz Carltons and the Peninsula a few times in Chicago, and I LOVE the Peninsula. Can never go wrong with a Ritz, however.

Like almesq, have never stayed in either but know both locations well. The only real benefit I could see to the Ritz Carlton on Central Park South is the potential for a room with a park view which could be quite dramatic. Central Park South is a bit touristy. The horse drawn carriages line up there. Not a problem in winter, just a "heads up".

You should have a look on tripadvisor.com for reviews of both. I think the Peninsula has an indoor pool if that might sway you. The St. Regis, right near the Peninsula is another to consider. Bottom line, you can't make a bad decision here, I don't think.