Annie

"Beaten by a little girl, HA!"

Gragas.

"I'll drink you under the table, scrub" after getting a quadra kill with his ultimate on a bunch of low hp champions grouped in a tight pack.

Karma, but I usually play Xerath when I'm mid so people don't dodge because "troll" even though Karma isn't bad and I'm much worse with Xerath.

Gragas, Cass, Xerath

Lux. Really strong with early laning, her ult can help in team fights incredibly, her shield is absolutely amazing if you can play it at the perfect time (often saving your team at the peak of the fight).

I mean just look at her kit.

Snare.
Shield.
AoE slow.
Giant burst laser with amazing range.

What isn't there to like?

Draaaaaaaven

Tryndamere

Leblanc, Dat burst

Twisted Fate bro

Nidalee hands down.. landing those max range spears that chunk anything and everything is very satisfying