Male
Support
Elise: versatile, evil woman with nice legs (hue).
Ooh, this is fun. Like playing Where's Waldo, but Waldo is a female player.

Male
currently Mid
Lux

Male
Top (Tank)
Shen: Ninja+Tank, that's about it, he blew my mind the 1st tiem I saw him, the guy is not only a flippin' ninja, but also a Tank (which is commonly my favorite type of characters in videogames), that was a combination that I've never seen before, to think that somekind of swift, fast and mobile warrior like ninja is a Tank, is something never crossed my mind before, when you say Tank, you normally would think of a big, hulky, heavy armored guy (kind of like Malphite, Galio, Rammus, etc.) but never a ninja.

Male
Mid/Jungle
Zilean/Shaco

Male
Top
Riven - Can do good to great damage as well as pretty good cc for crowded team fights.

Female
Mid
Lulu
(I love her CC and she's packed with personality. You can tell her voice actress put a lot of effort into her and she did a great job. She's not horribly difficult to play and she is a lot of fun to use. She's a very cutesy champion and I have an affinity for anything cute. I believe she is my most played champion close to Miss Fortune who I love to play with as my ADC. I've used Lulu in every role. Yes even jungle. ;x)

Gender: Complicated
Role: Jungle or support (Jungle in old season, not sure anymore...)
Orianna.

Her back story ripped my heart in two.

Male, Orianna (mid).

Male
Mid Lane
Katarina: Character-wise, she's vicious and bloodthirsty with a hard passion for her duty. Yet as ruthless and militaristic as she is, she remains to be sultry and sexy, and not even intentionally (doesn't say or do anything overly sexual, like some characters who actually try, i.e Janna, Ahri, etc). Design-wise, she's gorgeous. Hot bod, dresses for the kill lol. Gameplay-wise, just too fun. She gets in, does her work in a flash, and leaves everyone going "Whoa, what". Her animations and sounds are also really cool.

Whether gameplay, her design/model, or her personality/lore, this character feels all-around tailored just to my tastes. Love her.

(p.s for what it's worth, not a post-remake Katarina fan talking here. Loved her even before that, but it's double as much now <3 )

Gender: Male
Role: Mainly botlane. Draven or Lulu.
Poppy

People underestimate Poppy so hard, but after a lost teamfight, they regret it. I love it!