There's no better way to see Europe than by train. In terms of comfort, trains can't be beat. Most trains in Europe feature comfy, wide seats, great window views, and plenty of room for you and your luggage. Plus, you can get up and walk around without a stewardess yelling at you.
Trains also feature great amenities like sleeping cars and dining cars.
If you don't want to stir from your seat, bring your own food aboard or wait for a drink cart to reach your car. Another great thing about a train is that First Class is easily affordable, usually just a little bit more than the more commonly used Second Class. Europe is a much smaller scale and one perfect for the train. New York to LA by train is a recipe for stultifying madness, of watching an endless country go by day after day. In contrast, London to Paris is a mere three hours by the Chunnel.