You know the old saying about why people climb mountains (because they're there)? I feel that way about building tall skyscrapers (because we can). Just as humans will always be pushing to fly to the moon, then Mars, then somewhere else, I think we'll always be trying to build a taller building, and it's great!
I like to keep tabs on the construction of the Burj Dubai skyscraper which, upon completion in 2008, will surpass the Tapei 101 Tower in Taiwan as the world's tallest building. Here are some pics:
Artist's rendering of the finished product (with penthouse office suite possibly worldwide headquarters of The Blue Grotto):