Speedy or Dodgy?

I present here a pair of builds for Leona. They are both very similar and emphasize speed. They're intended for short, fluid skirmish-intense games and aggressive players who like to aid in pushes and ganks. Originally written for 3v3 play, I've found the second dodgy-speedy hybrid build is viable solo-top in 5v5's.

I can't offer any special credentials other than a bronze-silver range rating.

Pros

• 2.5 stuns
• Good armor/resistance
• Great initiator
• Fast: great for tracking down enemies, fleeing or providing cover during retreat

Cons

• Low damage output
• Hard to get direct hits with her ultimate
• HP a little low for a tank
• Passive requires teammates for benefit

Shield of Daybreak
Start with Shield of Daybreak for the opening gank so you can stun someone at the beginning of the fight, and probably once at the end as an enemy runs away or as you run away. Remember to intentionally attack after you use this ability, if possible, as you'll do additional damage. Use this ability against towers in the same manner. Eclipse
I emphasize Eclipse as a second pick and main skill because you end up taking a lot of abuse in lanes. It helps you weather attacks from ranged AD as well as casters and aids in farming. Try to position yourself between many minions for effective farming. Zenith Blade
Use Zenith Blade to latch on to fleeing foes, enemies trying to kill your squishies or to pick off minions. Be careful when you do this, though, as it will move you to the last hero in line that you hit. I refer to this ability as 'half' a stun because it stops the hero hit by it in place for about half a second. Solar Flare
Solar Flare has some great range - use it frequently as its cooldown is only ~60 seconds. If you miss it will still slow nearby enemies. Sunlight
Sunlight is really only helpful when you're with friends. I think it's better to lane in the bottom with a buddy and help than get kills as well as utilize your passive.
Important: Try to alternate between both points invested and actual use of your Shield of Daybreak and Zenith Blade so their cooldowns are roughly equal. You'll want to be able to use them in combination.

The item purchase order outlined above is detailed just for the beginning of the game. Most of it won't seem out of the ordinary.

Doran's Shield In 3v3 the opening gank counts for a lot. Every little bit of extra life and armor matters, and this composite item provides it. If you're not doing an opening gank or think you'll have a substantive edge in the first fight, skip to the regrowth pendant.
Health Potion Sight Ward You should buy these as needed throughout the game. Always ward the red lizard, dragon, and other bushes around the map.
Faerie Charm I find Leona runs a little low on mana early game. This item is cheap and helps to combat that, and builds well into the Philosopher's stone later.
Regrowth Pendant You'll take a lot of abuse in fights, this helps you save money instead of buying potions endlessly.
Boots Speed. Is. Huge.
Philosopher's Stone Generate some extra cash to help compensate for your so-so farming.

I try to complete this item shortly after the Philospher's Stone. It is part of what sets my build apart in a really significant way.

Speedy

Boots of Mobility
Combined with your speed Quints the Boots of Mobility make you amazingly fast. This becomes paramount as you dart about the map trying to save teammates and subdue feeling enemies. In 3v3 it's really easy to shift down to gank a nearby foe.

Dodgy

Ninja Tabi
The defensive provisions of these boots make them worthwhile as a kind of armor item. In games where speed is continually needed they should be added in addition to the Boots of Mobility. In games where speed is less important they can replace them. Combined with your runes and materies you'll get a decent dodge percentage, and with it, a frequent speed boost.

These can be mix and match depending on what the other team looks like and how the game is going.

Chain Vest Negatron Cloak
Your Eclipse Shield provides a lot of armor and magic resistance. Just one chain vest and one negatron cloak are enough to max out your needed toughness. If you're going with the dodgy build you actually probably won't need a full chain vest, a Cloth Armor will do instead. You can later build these items into better ones.
Kindlegem
Health and cooldowns are also important. The Kindlegem accomplishes this nicely, and will combine later. I usually add this item after basic toughness is covered, but if you're winning or needing more CC do it first.
Giant's Belt
If you can, add a Giants belt in to the mix for additional durability. You will need it for other items later.

Really, truthfully, I think it's best to be flexible for your final items. The base items gathered in midgame blend well into all kinds of variations, my favorites (which set this guide apart) are detailed below.

Force of Nature Since speed and quick recovery from brutal fights is very important to this build I highly recommend building your negatron cloak into this. Shurelyas Reverie
I find by late game you end up needing HP badly. The Kindelgem can be easily converted into a Shurelya's Crown, which can give an additional speed boost, cooldown reduction and HP. Rylai's Crstal Scepter
Turn your Giant's Belt into a Rylai's Crystal Scepter to add some more damage and ensure your enemies are always stunned or slowed in your presence! Moonflair Spellblade
This item helps you deal with CC and makes your abilities a little more powerful. Build it earlier or later, depending on the opposition.
But what about armor, you say?

Really I pick something that depends on the enemy champions.

• Ninja Tabi - As already mentioned in the mid-game items list, these can actually be used as your 'armor' item, especially with the hybrid dodgy-speed build. They are best against AD auto-attack champions, obviously.
• Sunfire Aegis - My most common speedy build pick - helps farm and do additional damage as you get in the middle of your enemy's formation.
• Randuin's Omen - A lot of people prefer this for the additional durability and the extra cash it provides on the way up (from the Heart of Gold of course). I generally think it's too expensive and not worth the additional protection.
• Thornmail - Necessary to counter high damage heroes like Tryndamire.

But What If...

If this happens swap:

• AP heroes nuke you a lot - Banshee's Vale for Force of Nature
• You get CC'd a lot - add a Quicksilver Sash
• They do lots of true damage - Warmog's Armor for Rylai's Scepter

If you somehow manage to make the game last long enough that you need yet another item toss in a Trinity Force.