My choice

Good for both offense and defense. With the items and masteries in this build, you will be extremely fast. After Using Ghost, no foe can escape.
Good for finishing off, as well as countering champions with build-in health gain (Vladimir), regeneration ( Dr. Mundo), life steal ( Nasus), Spell Vamp ( Morgana), or just someone who stacks The Bloodthirsters.



Good

If you are not a Ghost fan, this is an another great option. However, don't forget that Flash was nerfed recently (in 1.0.0.129 patch), increasing cooldown and decreasing the distance.
Good if you know you will face a strong AD champion like Tryndamere. _____________________________
This is another decent option. You can use Teleport for ganks, backdooring, saving towers, etc. _____________________________
Cleanse is a decent option, especially after the last patch (1.0.0.129), since it now removes Ignite and Exhaust.



Bad

Kinda useless, because the healing amount is very small, and the cooldown is long.

This better suits a tank. This spell has been removed from the game in 1.0.0.129 patch..

Leave this to your support.

You should not have any mana problems, unless you spam your Bladesurge like crazy, which you shouldn't.

I've played like 1.8k-2k games in LoL, and can't really remember anyone taking Rally. This spell has been removed from the game in 1.0.0.129 patch.

Pretty useless, if you ask me.

You are not a jungler.

This is a new spell, and at the first glance the attack speed bonus is nice, however this is not really a good choice for Irelia. First of all, you almost miss the AP component, because your skills have a bad AP scaling. Second reason is the cooldown of Surge which is just too long. This works better for an AP or a hybrid champion.

Not tested yet

After taking into account the recommendations on skill order, I decided to change it.


Hiten Style is maxed out first for two reasons. First of all, the true damage is good, since most of the top-lane champions are pretty bulky. Skills like Courage or safeguard/iron will, armor runes and items (as simple as that, huh) can reduce your normal attack damage badly. However, as long as you deal true damage on hit, you should be fine.

The second reason is the sustainability it gives. The health gain scales as 10/14/18/22/26. This may not seem too much, but in fact it is. On level 9, when you max your Hiten Style, you should have 83 damage.
That means that you need to have 31.3% lifesteal to get the same amount of health per hit as you get from your Hiten Style.
This gives you a lot of sustainability on the lane, and helps a lot when fighting another champion one on one (especially if it's a champion with life steal such as Warwick or Olaf).



The second skill I max is Bladesurge.
It's damage seems lesser then the damage of Equilibrium Strike, but that's wrong.
Bladesurge deals 20/50/80/110/140 (+1 per attack damage) physical damage. It also applies on-hit effects, such as the passive of Sheen and Trinity Force, meaning it actually deals lots of damage.
If you want, you can think of it as an empowered autoattack (but it's actually better since it is a distance closer).



Finally, Equilibrium Strike gets leveled last.
I used to max it our first, but really, the stun/slow duration increase is just 0.25 sec per skill level.
It also doesn't scale well. The AP scaling is just 50%, and considering you only get 30 AP from your Trinity Force, this doesn't look very well.
Getting a rank in this at level 3, however, is required to benefit from the slow/stun.
One second duration may not seem too long, but it actually is, especially if you manage to stun your enemy.




Needless to say, you should grab a rank in your Transcendent Blades each time it's possible.

I take these in 90% of my games. The best boots in the game. They will provide you the Magic resist you need, and tenacity bonus stacks with your passive, which means you will be almost not affected by CC in teamfights.
You can buy these if you have a problem countering your lane. They are very cheap, and will benefit you if you are facing an heavy-AD champion like Garen

Some people do not like these shoes, but i do. With this build Irelia tends to be a very fast champion, and these boots will make her even faster. However, if you get these, you will need to build your Philosopher's Stone into a Eleisa's Miracle for tenacity, or maybe get a Cloak and Dagger. I don't like either of those on Irelia, so only take these boots if you really need that movement speed.
I would not call them bad, neither would i call them good. The cooldown reduction is nice to have on any champion, but Irelia has rather small coldowns herself, so it's not that useful.
You are not an AP champion, why would you need this little amount of magic penetration? Don't know why did I even add them on the list...

Just for fun, I'm going to do some maths and give you the total damage that you will be able to deal with Trinity Force and ONE of the situational items above.
This may help you make a choice of what item to buy if you are having a good game.
The first column of the table represents an Irelia with just a Trinity Force, and all the other columns represent Irelia with Trinity Force and one of the situational items.

HOW IS THIS CALCULATED?
All the values are the ones at lvl 18.
All the damage values are basic, I know that they will be reduced by armor, blah blah blah.

I took the attack speed values from Leaguecraft champion builder, and I really hope these numbers are correct.

The number of attacks over 6 seconds would be (AS*6). This is always rounded down. The reason is simple. Imagine you have a value of 2.999 attacks per 6. This still means you will deal two attacks while Hiten Style is active, but the third attack will hit a little after Hiten style ended.

The number of critical hits is (number of hits)*(critical hit chance). This is simply rounded.

I guess you can figure out how to count total damage if you know the amount of hits and damage per hit xD

Please note, that the total damage of Wit's End includes the damage from the passive.



As you can see, if you only worry about the damage output, Youmuu's Ghostblade with it's active is the most cost-efficient item on the list, and Infinity Edge is the item that will give the most damage.

However, this does not mean it's the best one. All of the items have different stats (apart from damage), so you should always buy the one that you need most (like Hexdrinker if you need more MR and Wriggle's Lantern if you need more armor). Please, don't forget this, this table is just FYI :P