Just to throw in my 2 pennies in on the train vs plane issue. There are certainly advantages and disadvantages to both. Trains will never go as fast as planes, ever. Not only that, trains have to take a pre-determined path every single time (they're on a track), whereas planes can alter their route if necessary. So there's more flexibility and shortcuts in that regard.
Just like airlines, showing up just before departure on Acela or any other HSR service is going to cost more than purchasing in advance.
Even amtrak suggests to arrive at least 30 minutes before departure and some HSR lines like Eurostar (the chunnel) require you to check in 40 minutes prior. And some require you go through security (don't be surprised to see this in the US soon).
In many instances, one train can greatly affect the reliability and schedule of other trains because they all use the same track in many circumstances. This isn't as much of an issue for planes. Remember when a train got stuck in the chunnel last year? Not only did it shut down the whole line but a train full of passengers sat in the chunnel on the train all night.
Planes have a better safety record.
So over all, while there are definite pros for traveling via train, air travel offers more efficiency in terms of reliability and moving passengers more effectively. There is also more competition which can bring down prices.
HSR has come a long way and I am all for its development. Having traveled by plane and train (including HSR), plane travel is the way to go for me (although I am somewhat biased towards planes)