makin tracks
While I was still working that Olympics and trying to figure out my travel plans, I really debated on whether to fly to places or do a RailPass. It turns out RailPasses aren't the bargain the used to be and a lot of travel boards like Fodor's recommended against the train. There are also two European Airlines like Southwest that fly for next to nothing (literally 9 Euro from Torino to Paris for example - though a sidenote: if you fly them, check their baggage policies. After 25/30 pounds they charge you by the pound).
Taking the train was one of the best decisions about the trip. The trains are easy to use, run often. No lines or hassles or waits to get on. No advance reservations needed (so I could change my schedule as I chose). Generally you have plenty of time if you're at the station even 30 minutes before departure. My RailPass only came for first class, so seats and cars have always been large, roomy and comfortable. Thalys between Paris and Amsterdam even served meals like a US business class flight would. By far the French and German trains are the nicest. And it has also been a relaxing way to catch your breath between cities, watch the countryside, and prepare yourself for your next stop. Train stations in Europe are almost always in the center of the city, which is an added convenience.
So if you travel Europe, consider the train. Its shameful that the US has no similar rail system to offer.