League of Legends v1.0.0.130
Volibear, the Thunder’s Roar

Rolling Thunder: Volibear drops to all fours and runs faster if chasing an enemy champion. The first enemy he attacks is knocked into the air and flung behind Volibear.
Frenzy: Volibear's repeated attacks grant him additional attack speed. Once Volibear has repeatedly attacked three times, he can perform a vicious bite on his target.
Majestic Roar: Volibear lets out a powerful roar that damages and slows enemies. Minions and monsters are feared as well.
Thunder Claws: Volibear channels the power of the storm causing his attacks to blast his targets with lightning that bounces to other nearby enemies.
Chosen of the Storm (passive): Volibear heals rapidly for a few seconds when his health drops to a critical level.

Fizz

Urchin Strike's targeting updating to hit targets slightly earlier
Urchin Strike's attack component can no longer be dodged
Usability buffs. Yay.

Jarvan IV

Martial Cadence (Passive)
Damage changed to physical from magic
Damage changed to 6/8/10% (at levels 1/7/13) of the target's current health from 8%
No longer procs spell effects such as Rylai's or Spell Vamp
Increased the hitbox size of Demacian Standard when targeted by Dragon Strike

Tweaks and 'bug fixes' mostly. Nothing too drastic all around, but definitely a buff. A bit of a hit to his early game, but an equal buff to his late game, which far out-weighs the early game nerfs, imo. The damage change could be seen as a nerf, as it means he'll be dealing less hybrid damage, however if building armor pen, this will actually help his game more than it hurts it.

Karthus

Wall of Pain
Wall duration reduced to 5 seconds from 7
Now only affects a target once (instead of reapplying every pass through)
Fixed a bug where Leona's passive and the Dominion center Sigil could cause an immediate double kill against Karthus

Yay minor Karthus utility nerfs! He'll still be stupidly powerful, but this does help balance him out a bit.

Kassadin

Fixed a bug which caused Force Pulse to cast backwards after performing Rift Walk

Bug fixes, yay!

Katarina

Shunpo now always moves Katarina behind the target regardless if Killer Instincts is active

Actually a huge nerf to her laning, in my opinion. I was finding it to be incredibly easy to farm in lane with Shunpo, because I'd always end up in the right position to back away without taking damage. Once again, back to not playing Kat, I think. Sad days.

Kog'maw

Fixed a bug where where if you killed an enemy that exploded using Icathian Surprise, the enemy was awarded an extra kill (Shaco Hallucinate clone, Maokai)
Fixed a bug where Brand's Pyroclasm would give Brand an extra kill if it was traveling toward Kog'maw when Icathian Surprise triggered
Fixed a bug where if Ignite killed Kog'maw, it would cause Icathian Surprise to not trigger
Fixed a bug where Vayne's Silvered Bolts sometimes caused Icathian Surprise to not trigger

Huzzah, more bug fixes! I actually encountered the Brand bug. It was rather entertaining.

Riven

Blade of the Exile tooltip updated to display how much attack damage you will gain. It has also been clarified to state that Blade of the Exile scales off TOTAL attack damage, not bonus attack damage.

No one really cares, do they? Regardless. Good fix.

Sivir (Remake)

General
Attack range increased to 500 from 425
Attack missile speed increased to 1400 from 1200
Updated her attack frames to be more responsive
Base attack speed reduced to .658 from .679
Base attack damage reduced to 49 from 52.11
Updated recommended items
Fleet of Foot (Passive) – Remake
Sivir’s basic attacks against enemy champions grant her 50 Movement Speed for 2 seconds
Boomerang Blade
Mana cost reduced to 70/80/90/100/110 from 80/90/100/110/120
Damage changed to physical from magic
Bonus attack damage ratio increased to 1.1 from 1.0
No longer has an ability power ratio
Ricochet - Remake
Sivir’s next basic attack bounces to 5 additional targets dealing 20/35/50/65/80 (+ 1.0 Attack Damage) physical damage to the first target and 25% reduced damage to each subsequent target. 7/6/5/4/3 second cooldown. 40 Mana cost.
On The Hunt
Now additionally applies the buff to allies who come into range while On the Hunt is active rather than only on activation.
Attack speed bonus changed to 30/45/60% from 30/60/90%
Allied attack speed gain increased to half of Sivir’s bonus from a third
Cooldown adjusted to 100/90/80 seconds from 90

So i'm a little sad that they turned Sivir into a pure AD scaling pusher, but these changes are definitely a huge buff in her overall gameplay. I can definitely see her being a viable AD carry now, though with a bit more team utility than other carries, and a bit less direct killing power. She, however, will most certainly still be very deadly, especially with the minor buff in AD scaling to her Q.

Taric

Shatter ability power ratio increased to 0.6 from 0.4
Radiance ability power ratio increased to 0.7 from 0.6

These changes don't alter his supporting capabilities much, but they definitely help his offense a good bit. He was severely lacking in mid to late game damage output prior to this, so I'm actually very glad to see this change.

Vayne

Fixed a couple small bugs introduced to Condemn with Fizz patch

Bug fixes are lovely.

Yorick

Fixed a bug where Ignite's tick damage dealing the killing blow caused Omen of Death to fail to reanimate its bearer
Fixed a bug where Leona's Sunlight passive and the Dominion center Sigil could cause an immediate double kill against the Omen of Death target
Fixed a bug where if Ignite killed the Omen of Death bearer, they would not be reanimated
Fixed a bug where Vayne's Silvered Bolts sometimes caused Omen of Death to fail to reanimate its bearer

Bug fixes are very very good :D

Items

Health Potions now restore 150 health over 15 seconds (instead of 200 health over 20 seconds)
Madred's Razor
Proc chance increased to 20% from 15%
Proc damage reduced to 300 from 500
Mana Potions now restore 100 mana over 15 seconds (from 100 over 20)
Wriggle's Lantern proc damage reduced to 425 from 500

The Health potion nerf is what it is. It won't be game breaking, but it will also break some of the reliance on health potions, to some degree. Small buff to mana potions. Still won't be buying them often. Razor and Lantern nerf isn't actually as hefty as it looks. It's merely in place to go along with the nerf to jungle mobs. Good change, in my opinion. Razor, relative to the jungle, might actually end up being a slight buff. We'll see.

General

Chat window location will be now saved between games
Yay usability changes.
Improved the targeting algorithms; it should now be much easier to select units that are obscured
FINALLY! Last hitting with Nasus is SO irksome when the opponent is standing in the minion wave.
Damage from lane minions to champions reduced by about 15%
Minor, but notable.
Jungle Adjustments
Small camps now respawn faster, but have reduced rewards
Will hurt gank champions slightly, but help farm champions.
Small camps now have a Healing Sigil, healing the killer based upon how much health they are missing
Major buff to all of the squishier junglers.
Neutral monsters now have their health, damage, experience reward, and gold reward increase with game length, instead of having health increases with each respawn
Yay, reason to jungle in the later stages of the game.
Neutral monster experience range reduced to 400 from 800 (the killer always gets experience)
Definitely a good change. No more experience leeching, messing up people's jungles.
Ancient Golem camp experience increased slightly and gold reduced slightly
Will have to test the significance of this. It'll probably only balance out jungle paths a bit.
Crest of the Ancient Golem now grants 25 flat MP5, but grants 1% regen from maximum mana, from 1.5%, and provides energy
A relative buff to many of the junglers, but a nerf to some of the AP carries and mages. A good change overall, in my opinion.
Lizard Elder camp experience increased and gold reduced slightly
To balance the increased spawn rates, I suppose.
Blessing of the Lizard Elder melee slow % reduced to 8/16/24% from 10/20/30%
Not a huge nerf, but enough to balance out the reduced flash range, I believe.
Dragon and Baron Nashor are now immune to armor and magic resist-shredding effects
Not a huge change, but will help make them slightly more difficult for certain champions to take on. Not sure how I feel about this change yet.
Baron Nashor will now push wards away if you try to place one too close
A good change in my opinion. You used to be able to hide wards inside baron, which could prove quite irksome for opposing teams to clear, or even spot.
Monsters now heal 5% immediately when they retreat (instead of after 1 second), but are easier to re-aggro
Could be a good change. We'll see. Might break the mechanic that allows pulling individual jungle creeps.