It's ashame thats all you know of Joseph Gordon-Levitt, because he's developed into a fanatastic actor.
I saw him in that film with Heath Ledger a few years ago. 10 Things I Hate About You, I think it was.
That movie was in the 90's...
Joseph Gordon-Levitt has had great performances in The Lookout, Brick and Stop-Loss recently, check those movies out.
I haven't seen Stop-Loss, but I definitely second The Lookout and Brick.