Mine is Arcade Riven. https://s-media-cache-ak0.pinimg.com/originals/6b/8e/f1/6b8ef1b54cbe5c67ee20badeb1980ecd.jpg
Ty Zeronis for designing this awesome skin. I love it so much I'm gonna make a cosplay for it. With lights and all!
PS, I've always considered Arcade Riven to be male.
I'm curious to know which one skin is your absolute favorite in the entire game. You know that one special skin that makes your jaws drop, knees weak and eyes water
DJ Sona Arcade Ahri Santa Braum Gragas Caskbreaker
My favorite is Star Guardian Jinx. It gives her a new look and feel while keeping her personality intact, gives her cool animations and particles, and has the best ship-tease in the world.
SG Jinx X SG Lux, amirite? Listen to them voice lines.
Dragon Trainer Tristana
PAX Jax. I wonder if anybody remembers it nowdays.
Havent played it yet but as a Zyra main, im already gonna say Dragon Priestess Zyra. I WILL buy it day one its on sale. Ive been waiting for a skin for soo long and that one is beautiful and reminds me a little of kerrigan from starcraft. I get to play my favorite champ AND look like the queen of blades???? YES PLEASE
This skin is litterally amazing right now, and I hate the fact that I can't buy it :<
My personal favorites are Dragonslayer Pantheon, Noxus Poppy, and Hyena Warwick.
All the Sion skins aren't really any better than his base. Except maybe Mecha Zero, but I don't like Mecha Zero (too bulky).
Champion Thresh tbh
Hard to pick between Thunder, Mystic, Shadow, or Air Lux. They're all amazing.
Also Zyra default after update.
Victorious Morg and Elise.
The entire Elderwood line.
Definitely Not Vel'koz and Forecast Janna always make me smile.
Astronaut Teemo.
http://i.imgur.com/QVdgoUs.png
but for me, there are too many skins that i really like tbh :<
Mine is Foxfire Ahri, it is the first skin I ever bought for her and have one tricked her ever since http://www.tapeciarnia.pl/tapety/normalne/181210_league_of_legends_ahri.jpg
Grim Reaper Karthus
Because it shows the dark fate that awaits all of creation and the only certainty of existence.
Urfrider Corki.
Infernal Nasus..
Smoke weed everyday.
Right now prestigious leblanc
https://i.ytimg.com/vi/-nuelu_6e5s/maxresdefault.jpg
I can't help but love this skin. It's awesome.
This celestial beauty, Cosmic Reaver Kassadin.
Does pax jax count just because I have it and most people don't?
Favorite in overall design though would probably be Star Guardian skins though since it brings bad some fond memories of childhood cartoons.
Is my age showing again? Has it really been 6 years since I started playing?
Cant decide between Blood Moon Jhin , Warring kingdoms Azir and Gravelord Azir ;_; so i will go for all of them 3
<3
Blood Moon Jhin, with Blood Moon Talon second
Mine would be a mix between Pulsefire Ezreal (I have this skin) and all skins Yasuo has.
But seriously, PFE needs a VGU. It's like, 4-5 years old right now.
Sun Goddess Karma.
Hands-down the best skin - bought it before the splash updates too. http://4.bp.blogspot.com/-rtHxTHF0Wxw/VKVmyEjpa2I/AAAAAAAAAqI/OeV_ggjPgQ4/s1600/karmaturn.jpg
Gorgeous. (Best rack in the game too imho)
But Skins don't follow rule 63...
Anyway, mine is probably
Sweatheart Sona 
I love all the heart effects because they remind me of Kingdom Hearts :') I think I've actually ended up playing that skin the most, even though I own all the Sona skins.
Honorable mentions of second favorite skins goes to:
Muse (I love the classicism)
Hexteck (because I like the colors) and Star Guardian (which I need to buy TT~TT)
Bewitching (she's so beautiful <3)
Popstar (because I'm #basic)
I love a lot of skins, but I guess I'll just say Bewitching Nidalee for the sake of discussion.
Obviously Elementalist Lux cause Lux main
As I do love that skin, I think I like Blood Moon Jhin more due it's aesthetics and Jhin's a much more interesting character.
It's definitely hard to pick one skin out of hundreds
Head Hunter 
is my personal favorite
