Cowboy Bebop: Heaven's Door (2001)

Basically a big-budget feature-length version of one of the series' episodes, specifically one of the moody philosophical type with comedy touches where you get to see how the fucked-up world fucks up the people within it and how they develop out of and respond to that, rather than one of the full-comedy episodes or one of the heavier personal drama episodes. Definitely worth the watch if you liked the main series or melancholic used futures.