One of the many brilliant-but-canceled FOX television shows is Terminator: The Sarah Connor Chronicles. If you're a fan of the movies at all, you'll enjoy this action-packed, tightly written show. I myself missed this show while it was on the air, but thankfully Netflix Watch Instantly has both seasons available.
I just started Season 2 and was blown away by this scene:
Now that Party Down isn't on Netflix Instant anymore, this gets my vote as the show to watch online.