10. Louie (2010 - Present)
For the sum of three ingenious seasons, Louie - written, directed and starring stand-up comedian Louis C.K. - cemented itself as the best comedy show on television. Not only did Louie break the rules of the sitcom, but it redefined the genre for a new generation: for three wonderful years, episodes remained clever, unpredictable and hilarious, but they were also surreal and crazy and plainly weird. In short, there was nothing else quite like it.
Then something happened during the fourth: presumably of the mind that whatever he did would be received with unconditional love and support (pretty much because everything he'd delivered up until then had been), Louis C.K delivered a season comprised of melancholy, interconnected episodes, breaking away from the "extended" vignette format that had made the show so great up to that point.
The big problem was that they weren't very funny, and there was an uncomfortable feeling that C.K. had accidentally wandered into the realms of pretentiousness. The season wasn't a total disaster or anything, but - all in all - it felt like a step backwards.
Praise to God, then, this was remedied when the hilarious fifth season arrived. Not only did season five feel like Louis C.K. addressing the faults of the fourth, but the season somehow came away feeling like the freshest one yet - a reinvention of a show that had already done so much reinventing. Still, for a minute there, things looked kind of rocky.