Skins don't provide (much of) a competitive advantage or disadvantage, but imagine if they did. Compared to the stats of your main in his/her/their base skin, what would your favorite skin's stats be? (That means both base stats and spell stats.) (If your favorite skin is the base, then choose your second favorite.)
http://leagueoflegends.wikia.com/main/category/Released_champion can be used for reference.
Super 
: Gain 1 gold every time he kills a Superb Villain Veigar.
Superb Villain 
: Gain 1 gold every time he kills Super Teemo.
Justicar Aatrox:
Champion actually becomes viable.
Star Guardian Lux (can be applied to Janna and Lulu): gain 1% increased shielding power when shielding the Sun.
---> 
You know what? I'm gonna do it. You hear me Aqualious18 and all you other non-believers? I'm gonna do it and you can whine about it for days and downvote me into oblivion, but I'm gonna do it! Valoran needs its heroes even if their skins aren't a reality yet...
Health 540 550 +90 (She's a tad healthier with more modern medicines and food)
Attack damage 56 +4 +4.5 (The longer the battle, the quicker it has to end.)
Health regen. 8 +0.8 10 +0.9 (She can't back away from the fight so soon!)
Attack speed 0.625 (+ 0 +2.5%) 0.750 (+ 0 +2.2%) (The hammer's heavier being made of thick steel and all.)
Mana 280 +40 260 +42 (While it's a bit harder to cast as freely in heavy armor, the power reserves help out a lot as you upgrade.)
Armor 29 +3.5 30 +3.8 (This isn't your average light armor, no.)
Mana regen. 7 +0.7 (Although one might expect it to be less power-conservant, there's actually some motion turbines built in to compensate for that.)
Magic resist. 32.1 +1.25 31 +1.15 (They cut out some of the insulation in favor of plating.)
Melee 125 125.04 (Because, reasons.)
Move. speed 345 330 (The heavier the armor, the slower the warrior.)
Popstar 
Gains 1g per Champion (ally or enemy) per second that she Dances within 1000 Units.
Dragon slayer skin like bonus DMG granted when slaying a dragon
Bioforge dyrius Hextect Items give him Ap scailing on his ult 100%
Cryo core makes Passive no longer do DOT but slow instead
Default 
literally the exact same
the end
Final Boss Veigar
Health: 560 (+83) Health regen: 7 (+.8) Mana: 425 (+64) Mana regen: 10 (+1.1) Attack Damage: 50.71 (+1.8) Attack Speed: 0.625 (+1.85%) Armor: 37.25 (+4.25) Magic Resistance: 30 (+1.5) Range: 475 Movement Speed: 330
Passive - Phenomenal Evil Power: Now grants Health, Health Regen, Mana, Mana Regen and Movement Speed as well as AP; bonuses now 3 Health, 2 Mana, 1.5% base Health Regen, 2.5% base Mana Regen, .25% flat MS (including boots, stacks multiplicatively with other % MS boosts) and 1 AP per stack. Basic attacks now deal an additional .5 damage per stack.
Q - Baleful Strike: Now a piercing line skillshot, and deals 60/100/140/180/220 (+50% AP) (+1.5 damage per stack of Phenomenal Evil Power) to all enemies struck.
W - Dark Matter: AoE doubled and now deals 100/150/200/250/300 (+90% AP) (+2 damage per stack of Phenomenal Evil Power).
E - Event Horizon: Now additionally shields Veigar for 5 per stack of Phenomenal Evil Power if he is within the cage when it spawns. Now grounds all enemy units within the cage, but stun duration down to 1/1.25/1.5/1.75/2s.
R - Primordial Burst: Now a piercing line skillshot that deals 25% reduced damage on each successive champion struck, down to a minimum of 50%. Damage now no longer scales with missing HP and instead deals 250/375/500 (+100% AP) (+5 damage per stack of Phenomenal Evil Power). Damaging enemies now reduces the cooldown of Primordial Burst by 1 second per hit per champion. Base cooldown changed to 130 / 115 / 100s.
Stats worthy of a final boss.
bladecraft 
Health 99999999999999999 all levels Attack Damage 99999999999999999 all levels Health Regen 99999999999999999 all levels Attack Speed 99999999999999999 all levels Mana 99999999999999999 all levels Mana Regen 99999999999999999 all levels Magic Resist 99999999999999999 all levels Armor 99999999999999999 all levels Movement speed 99999999999999999 all levels
's new Aether Wings give her +2500 movement speed the lightsaber E grants true damage.
Project 
sword doesnt sound like rubber Chosen can use the force
Demon Blade Tryndamere Passive add-on: Gain 1% attack speed and .25% lifestyle per missing % of health.
Super Galaxy 
: Can not die, unless all members of the enemy team have done damage to him in the last five seconds.
When using his ultimate, he will stun all enemies on the map, no matter where they are, so that they have to watch this glorious anime scene... even though they should be attacking him. The stun lasts until the ult disappears.
Shouts: "JUST WHO THE HELL DO YOU THINK I AM?" as a global taunt whenever he gets into combat with anything. besides monsters.
All players in the game are forced to watch him spawn into the game and can not turn their cameras away.
Now has a 3rd bar called "Fighting Spirit" it increases by 1 for every spell that he lands on an enemy champion. Increases by 1 for every tick of damage from Flame Spitter and The Equalizer.
When "Fighting Spirit" reaches 100, Rumble automatically gains +9999 in every stat, becomes unkillable, and is no longer affected by true damage.
Renegade Talon. He gets a good laning phase but lower scaling due to stealing cheap blades.
Eternum Nocturne:
0 Armor. 0 MR. Double attack damage and attack speed scaling.
Hnnnnnng. Edit: why am I the only person doing major changes to stats. Everyone else is doing like +1 gold.
Earnest elf Tristana...
The more kills she gives.. As in her assists.. +1% damage.
Phoenix Quinn : Her attacks apply ignite
I have many a mains. I have one or two for every lane. Lmao. But if I had to choose i'd choose my first ever main.
Dragonslayer Pantheon
Increased health, armor and mr.
Q now adds a DoT effect scaling with AP with a base of 100/150/200/250/300 damage at each level. (Not counting Dragonslayer stacks)
W now physical damage and causes bleeding.
E New Passive: if Pantheon kills a dragon, or assists in killing a dragon, Pantheon gains bonus AD and the DoT on his Q does more damage. (Kills 1% per dragon. Assists .5% per dragon) With a Max of 6 dragons.
R now does physical damage and causes a burning effect on enemies hit in the area.
Astro-
all knock ups last twice as long due to low gravity!
Grim Reaper Karthus would be immortal, so I'll do Statue of Karthus instead.
Karthus stats:
Health: 516 (unchanged)
Health Regen: 6.42 -> 6.0 (he no longer regenerates as quickly because his robes are bulkier)
Mana: 372.48 -> 488 (the powers of freedom instill in Karthus extra energy)
Mana Regen: 6.0 -> 7.0 (see directly above)
Range: 450 (unchanged) -> 20000 (freedom, yo) (thanks Nub Lux, this buff suits Karthus well and also maintains his perfect state of balance by offsetting the health regeneration nerfs)
Attack Damage: 45.66 -> 46.66 (the powers of freedom inspire Karthus to swing his staff slightly harder, causing the ghostly projectiles to hurt slightly more)
Attack Speed: 0.625 -> 0.90 (the powers of freedom whip Karthus into a fervor, causing him to attack faster. His windup will still be terrible though.)
Armor: 20.88 -> 26.77 (Karthus's robes make him harder to hurt)
Magic resist: 30 -> 45 (the powers of freedom protect Karthus from magic)
Movespeed: 335 (unchanged (inspired by the powers of freedom, Karthus moves faster, but he has heavier robes so he moves slower))
Death Defied: 7 seconds -> 8 seconds (powers of freedom, yo)
Lay Waste: Unchanged
Wall of Pain: 40/50/60/70/80% slow -> 10/20/30/40/50% slow (Karthus feels bad about obstructing other's freedoms with his wall)
Defile: 30/42/54/66/78 mana per second -> 0 mana at all ranks (let the souls be free)
Requiem: 250/400/550 damage -> Two waves of damage, 1/1/1 true damage followed by 250/400/550 damage with 20% cooldown refunded for each champion hit
(freedom, yo)
Forget it. My favorite's not even a real skin.
Dark Star Thresh.
Oh my.
Arcade 
While using Missile Barrage, Corki performs a barrel role which deflects all incoming projectiles. Does not deflect ultimates however.
Jaximus He has a real weapon so uh, infinite everything.
Snow day gnar. Automatic frozen mallet passive.
Kitty Clarissa10/28/2016, 3:38:04 PMArcade Sona,
She has increased buffs on her abillites
lel .
