Spain/Portugal/Gibraltar - Paris to Barcelona: Train or Plane?

Planning to travel from Paris to Barcelona. Not sure of whether to fly or take the train. If i take the train, it will most likely be during the day. Is there anything to see from the train. Is it worth taking the train? Seeking recommendations from anyone who has traveled these routes as i need to make a decision soon.

Thank you. :)

Having taken the reverse route, Barcelona to Paris, I cannot more strongly recommend flying.

I haven't done this route but I recently read (http://www.elmundo.es/elmundo/2010/12/19/barcelona/1292752583.html)that the trains from Paris to Barcelona now take 7h25 instead of 8h40 because you can take the TGV all the way to Spain (Figueres) and then connect to Barcelona. It mentions that it costs from 63 to 130 euros.

(it's still a very long train ride...)

Is there a reason you can't do the overnight train? I did it a number of years ago and found it a rather pleasant way to travel. I was pretty well rested when I arrived in Barcelona.