I already posted much of this info in the Lounge in response to billyskank's thread, but it occurred to me that it might last longer and be more useful to more people in this forum.
For great train experiences, go to Japan:

This is the interior of a Shinkansen "bullet train," standard coach. Plenty of room, the seats can be flipped around to create groups of four, and vendors come by constantly selling tea, coffee, beer, sake, snack foods, and box lunches.
Here's the exterior of one of the newer models. It looks like a lizard.

This one looks like a racing car:

Here's the route map:

But you don't have to travel far to enjoy the trains. Here's a map of the Tokyo-area surface rail and subway systems:

The solid dark lines are surface trains run by the JR (national) railroad. If you get a Japan Rail pass, you can ride those (along with most Shinkansens and intercity trains) for no extra charge.

For the others, you can get a Passnet debit card in denominations up to 5000 yen ($42), which automatically deducts your fare at the turnstyle.

In the Kyoto-Osaka-Kobe area, you can use the Surutto Kansai card, which operates on a similar basis.

Riding the trains in Japan makes you realize how backward the U.S. is in terms of intercity and intracity transit. While we dismantled our passenger rail system, Japan allowed its systems to evolve and modernize.
Meanwhile, other Asian countries, including South Korea, Taiwan, China, and Thailand are starting to copy the Japanese approach to transit.