I am guessing the NYC/DC train corridor is nicer than what we have on the west coast. I was looking into a holiday ride through silver country here, and the reviews unfortunately came back a big "heck no."
http://en.wikipedia.org/wiki/Coast_Starlight
I find train travel to be super relaxing - check it out sometime if you get a chance.
Whereas sometimes the mindset "the journey not the destination". That's when you can appreciate a train, ocean liner, bicycle, or feet.
Having said that, Acela is usually the best of both worlds.
That said, you go much further than New York and the train makes less sense either in terms of time or money.
Train gets a lot less interesting as an option as the distance increases. I have taken Amtrak from Boston to Washington and it's definitely doable but it's not really especially competitive with flying .
My long distance travel has been exclusively by Amtrak for the past ten years. I live in Chicago, which is pretty central to the system - I might not have been so strict if I lived somewhere else.