From personal taste I like modded survival series that bring something different to the table. Not to hate on those people who do them but Hexxit and Vanilla survival series are not interesting anymore in my oppinion. Pick out a nice modpack or something and create a series that has a special purpose. The Yogscast are doing a modded survival with the goal of reaching space, I am starting a modded survival that involves pvp, fortress building, exploring, survival and capture the flag with multiple people. You could even do Hexxit but have a unique twist to it and some sort of new goal to reach.

Of course you could do other games or mini games that do not have much coverage

Goodluck