I took InterCityExpress (ICE) trains a lot when I was in Germany, usu. on the "sprinter" run between Muenchen + Frankfurt and also a few to Hamburg and Berlin.

The cabins are wide and spacious and what I liked the most was that between trains were often large panels of glass so it felt like you were looking out on a film landscape..

In the US I always try to take a train instead of flying (shhhh) -- on the west coast, you can earn AS frequent-flyer miles, and sometimes UA miles with Air Rail.

Trivia question: what is Amtrak's two-letter "airline code"?