Skins! First of all, it's relatable. Either you did something one of the characters did, or had a friend just like one of them.
The topics covered by the show were things every teen faces....like school, grades, popularity, peer pressure, drug use, and sex.
In addition, the actors on the show were great! Quite a few have gone on to do other projects, and be very successful.
The show definitely holds up. Easily one of the best show! :)