As several of you mentioned, Clone Wars is very easy to run in the background while doing other things. I've seen the entire series maybe three times now just leaving it on while I work, cook, etc. I watch Rebels just to keep up with everything SW, but Clone Wars was leagues better.
I would like to rewatch Firefly. I've only seen it once. Serenity was good, too.
[member="Braith Achlys"] Loved Warehouse 13, but none of the streaming services will put up the final season, so I don't know how it ends. On that same note, Eureka was a lot of fun.
Lost is one of my favorite shows of all time, but after watching it as it aired the first time then rewatching most of it with my roommate two years ago, I don't know that I have it in me to go back (haha).
Supernatural is fun and easy, especially the early seasons with more stand alone episodes. I think around the 3rd season was my favorite, but the show still keeps me interested today.
Flash Forward and Persons Unknown were each one season before canceled, but I enjoyed both a lot.
[member="Fabula Caromed"] do you know where I can stream Cowboy Bebop legally and free? I only see the undubbed version on Hulu, and I am pretty busy, so I work and do other things while I watch, and that does not work well with subtitles. I am not a huge anime fan, but I think I could enjoy this one.