On the RailEurope website I'm seeing fares ranging from $115 (early morning) to $257 (late afternoon times) for Eurostar on 11/10. If you factor in transportation to and from airports, the $257 is not really much more than the flight. The train is faster and gives you a much more enjoyable experience. The 6:45 AM train for $115 is a bargain, but you'd have to give up time in Paris if you left that early.

Got my two cents in before this gets moved!