I have recently gotten into long-form magazine articles, and I encourage you to check out Kevin Kelly's list:

http://www.kk.org/cooltools/the-best-magazi.php

Plus http://longform.org/ and http://givemesomethingtoread.com/ are both excellent.

Neal Stephenson's "Mother Earth, Mother Board: Wiring the Planet" in particular was formative for me as a teenager.

http://www.wired.com/wired/archive/4.12/ffglass.html