Pitched as a combination of The X Files and Dawsons Creek, Roswell just about sustained three seasons with an often witty sometimes soapy story of aliens living as teenagers.
The outsider metaphor is sometimes overplayed, but the first series packs a hell of a lot of action into its run as the extraterrestrials come close to discovering their origins, and form potentially icky relationships with their human classmates. The only problem is that it leaves itself with very few places to go.