I think that flying is the best experience too - you get a chance to be up where the atmosphere is thin, and where you can see everything below you! Takeoff is the most exciting part.
Especially if you take off just as the sun rises or sets - a few years ago I was on a flight from the UK to Turkey, and there was a thick layer of cloud covering the entire sunset sky. We climbed quickly towards the cloud, and after a few seconds of being immersed inside it, we punched out through the top of the layer and spent a few seconds skimming right above it as if it were a landscape - I could see the bumps and 'hills' in the clouds just a few metres below the wings going past at hundreds of miles per hour, and it looked just like a very low flypast of a hilly landscape. Venus was hanging there too, and the sky above the cloud landscape was perfectly clear.
Flying into the Maldives is an amazing experience too - the airport is nothing more than a runway in the middle of the sea, and you are skimming just above the water until the instant you touch down. Then you fly in a seaplane across the atolls of islands.
The most thrilling thing that I think I've done is to land a small Cessna 152 - it has nowhere near the pulling power of an airliner - it just feels like a little flying car, but even holding the controls is enough to give me a big thrill XD