the tallest building (architecturally) is Taipei 101, located in Taipei, Taiwan. it looks like this:

http://www.skyscraperpicture.com/taipei01.jpg

looks quite a lot out of place, doesn't it?

it has 101 stories above ground and 5 below and has built in fibre optics that allow internet transfer speeds of 1gb/second. imagine how fast your Lost torrents would download then! tee hee.