1) Hunter Predator. Really enjoy the amount of different setups and combos. Also you can play it aggressive with htb's and stuff or go for a bit slower GM-like approach. Loving the character, just not very strong in the meta right now.
2) Assassin Kitana. My go-to for serious play. Been my main through the game. Can't even say what it is what I like about her, she just... works.
3) Broodmother D'vorah. A bit like hunter but with good mids and antiairs. Dvorah is just fun to play. She feels so quick and nimble with her normals and runspeed. NRS really did amazing job with her.
4) Warrior Predator (best brutal in game, also suprises many off-guard)
5) Swarm Queen D'vorah (RIP puddle)
6) Covert ops Sonya
7) Tarkatan Alien
8) Mystic Ermac
9) Spectral Ermac (I'm so bad with him but he's so much fun)
10) Cryomancer Sub (post-patch cryo is fun, prepatch he was maybe the most boring character in game)