The biggest winner is, justifiably, California, which is getting $2.25 billion for its truly high-speed rail plan that passed as a voter initiative (or was it a referendum?) in 2008 along with the hated Prop 8.
Truly in that it actually will be really high-speed like the trains of Europe, Japan and now China.
For great coverage of California's High Speed Rail, I would urge you to read my friend Robert Cruickshank's excellent blog devoted to it
Initially, it'll connect Los Angeles to San Francisco. That trip will be approximately 2 hours and 40 minutes each way, compared to the 6 hours by car it takes along Interstate 5. It's also going to make for a quicker trip point-to-point than flying would for many people, given the major amount of time you have to spend going to the airport, waiting in so many lines, waiting for a whole bunch of other things, etc. etc.
A similar speed train would get you from Boston to Washington DC in less than four hours (maybe even only about 3 hours 30 minutes), making it frankly competitive with air travel as well.
Such a train would be hands-down fastest by quite a bit to get from New York to anywhere on the Northeast Corridor, given the terrible airspace congestion leading to major delays in the New York area and the fact that it's in the middle (though closer to Boston)
Of course, what would be really amazing would be a Maglev train (up to 350 mph) from Boston to Atlanta