Dunno if its too late to post here, but Rotom-C is probably the one Pokemon i just can't stop using in RU, its just sooo useful for many different things. Electric/Grass with Levitate is a pretty nice defensive typing with a lot of cool resistances such as Electric, Water, Grass, and an immunity to Ground. This and Volt Switch makes Rotom-C probably one of the best offensive pivots in RU imo. The Choice Scarf set is one of the best revenge killers in RU , as well. I also like using Rotom-C in UU whenever i play there (admittedly not much .-.).
I also really love to use CB Entei and various Normal- and Flying-types such as Tauros, Zangoose, and Swellow, but i think i've used Rotom-C on far more of my successful teams than any of them.