Plex, my Mac, and my Apple TV

Hey guys, I've recently discovered just how great Plex can really be. However, I'd like to know what kind of content you guys upload to your Plex servers. What kind of movies or TV shows do you guys watch? Also, where do you get all your content? I've been downloading some movies from iTunes, but it's proving to be pretty expensive. So are there any competitors that you've found to be relatively cheaper? Thanks!