Metro rail has its place, particularly in large metropolitan areas. $20 to go from San Diego to Oceanside with AC outlets yet without I-5 traffic is superb. I'm a fan of the WMATA Metro (DC area) as well.
For an inter-city high-speed offering, I'm fairly skeptical. We have Amtrak and compared to air travel it costs just as much yet takes several times as long to move me across the country. It would have to be a high-volume route with a proven market for me to support it.