I'll take the Eurostar from London to Paris even if it's slightly slower because it's just a nicer experience. But much further and I'll probably fly unless I'm making a point of taking a train for fun. The only other case would be if I'm taking a lot of luggage as that's much easier to do on a train. Back when I only had a big bulky laptop I might prefer a train to work on but these days my ultrabook is usable on a plane.