6. Manic (2001)
Likely the least-known - and therefore most under-apperciated - film on this list,
Manic is an excellent indie gem that marks the first collaboration between Gordon-Levitt and Zooey Deschanel, before they would again play romantic leads in the wonderful
(500) Days of Summer. The two play inmates at a juvenile psychiatric ward; Gordon-Levitt's character Lyle is admitted there after a violent attack on another teen, spurred on by the kid making jokes about Lyle's abusive father. From here the film develops as a gritty but tender meditation on mental illness, family and romance, with the actor delivering one of his most anguished and sympathetic turns to date. While delivered on a paltry $1.5m budget, this in effect only added to the film's pared-down, simple appeal; it is more interested in its characters than stylistic flourishes, providing Gordon-Levitt with a stellar platform on which to showcase his talents. It's not nearly popular enough, and if you haven't seen it, you absolutely must seek it out.