Virgin trains are good, and advanced purchase first class tickets can be great (depending on day / time, you get a meal, wine etc included). The time of day really affects the prices, so travel after the morning rush hour and before or after the evening rush hour and you will often see a huge difference in prices. If you are coming back by train, book it as a return - when I did this a few months ago, it was 1 GBP more expensive to book the return at the same time!