Many people play him traditionally as an AD/DPS champion, which is okay, in my opinion, can allow for a massive amount of damage in the way of auto-attacks and some nice damage with abilities. In my opinion, this build is no where near as useful as it was back when Lee Sin first came out, with which I almost had a pen-ta-kill in my first game with it. I did however, find out later, that the build only works if you can get fed early game and stay ahead, while the Tank/AD build is great for early game survival and allows for massive late game damage. My recommended build would have to be the second one, since I am really good with tanks and some AD carries and this build combines the best of both worlds, and capitalizes on an above average health total for an AD carry.

Pros

+High AD champion that can deal great burst damage
+Can take a hit (if built properly) and not lose out on damage output
+Can knock up the entire enemy team
+Can turret dive and get out very fast
+Reminds us of the good old days of Chuck Norris and Bruce Lee

Cons

-Bad timing with his abilities can almost always insure an easy kill for the enemy team
-Not great without his slow, so keep this in mind
-A miss with his Resonating Strike/Sonic Wave will disappoint you if the enemy is under ten percent health and is getting away
-Bad map awareness in relation to where enemies are before turret diving will ensure almost certain death
-Stun champions are very bad for you

I always recommend that when you play Lee Sin the Runes:

Marks

For marks I always recommend Greater Marks of Desolation
Gives more oomph to your hits.

Seals

For seals, I always go for Greater Seals of Resilience
Gives more survivability against AD champions. Great substitute would be Greater Seals of Fortitude.

Glyphs

For glyphs, I always go for Greater Glyphs of Warding.
Gives more survivability against AP champions. Great substitute would be Greater Glyph of Focus.

Quintessences

For Quintessences, I always recommend two Greater Quintessences of Fortitude
and a Greater Quintessence of Desolation.


Please note that the runes can be changed based on your playing style. Please play responsibly and experiment to see which build and runes fit the fold for each character that you play.

I always go with the 21-0-9 approach, with slight variations depending on how I want to play Lee Sin. While for a tank build you can go 0-21-9 or 9-21-0, my suggestion is stay with the AD on the Mastery Pages considering that the Rune page is already tank-like. However, the game is most fun based on your personal style of play, so I would have to say that their is some validity to 0-21-9, but you usually end up with not enough early damage in my opinion.

Recommended:

The EXHAUST and IGNITE combo. This is a traditional favorite for any high ad champion because at the beginning of the game it allows you to almost always get that last hit. Plus, if you play 3v3's a lot, you'd see that if all your teammates and you IGNITE one champion it almost always equals am easy first blood for your team. (Helps set the tempo for the rest of the game.)

Great Alternatives:

Replace EXHAUST with a either a FLASH or a GHOST. Works great with Lee Sin because of his abilities, but the FLASH works best.



If you plan on jungling, always go for the SMITE and the Mastery that goes with it. This would replace the IGNITE, and allow your teammates to get a really high level and gain an edge on a lane and helps you in the ganking department.

Not Recommended:

All other summoner spells are pretty much useless for Lee Sin except for RALLY, HEAL and REVIVE, however, you'll find that most of the time your alive that the RALLY bonuses are too small, the HEAL works but not as well late game, and the REVIVE is only for those players who plan on staying dead half the game and want to get back in the game.

All the items in the build are great recommendations, but let me stress the importance of choosing the proper build for your playing style.
Note: I always go either boots and 3 health pots first, a Doran's Blade, or a Doran's Shield first.

Tank/AD Build

Core:
Mercury Treads work best in any tank build in my opinion because of the Tenacity attached to them, which shortens the duration of slows and stuns and provides nice M. Res. and movement speed.
Warmog's Armour is hands down the core of this build. It boosts his health by 1500 and gives him 45 health regeneration for a champion that has health at just under 2000 at level 18.
This is the item that solidifies this build as useable. Atma's Impaler gives a nice critical chance (18%) and armor, plus it gives a nice bonus of 2% of your total health is converted into attack damage. Works like charm and is the hand to the glove for this build.

The next items are situational items. Get them in the order that is necessary for the current damage output of enemy champions.

Recommended items:

A Force of Nature, A Frozen Mallet and a Bloodthirster.
These items give nice stats, as your health is now over 4080, your damage is over 350, and your M. Res. now blocks 64% magic damage from incoming enemy champions.

Good items to consider and situation:

Situation 1

The enemy team has a Karthus or any other high burst champions with an ability that does massive damage. Solution: Banshee's Veil (replace force of nature)

Situation 2

The enemy team has a high DPS champion who wreaking havoc on your teammates.
Solution: Switch the Force of Nature for a Sunfire's Cape

Situation 3

The enemy team is too far behind and you are having problems owning them before they can get away, despite the Frozen Mallet.
Solution: Switch the Frozen Mallet or Force of Nature for a Infinity Edge.

AD/DPS Build

Core: Berserker's Greaves, Frozen Mallet, and Phantom Dancer
These items allow you to pretty much almost anytime chase down the enemy as they are trying to run away, and with Frozen Mallet you get a nice hp boost.

Recommended items: Infinity Edge, Bloodthirster and Hextech Gunblade
These items give you massive damage, life steal, spell vamp, and greatly helps your ability to do massive damage with your abilities.

Situational items:

Highly Recomended
If the game goes beyond long or you are just doing so good, sell your boots and grab another phantom dancer. This allows you to take out turrets with ease and constantly deal damage to enemies without losing key movement speed.

Other:
Any of the tank items listed above but the core build. Warmog's will almost profit you nothing without an Atma's.

Note: This build is for people wanting to learn how to play the Blind Monk well.

Note: Level up each of the basic abilities first (Q->E->W), based on the priority listed near the end. I would recommend having all them by level 3.


Always level up resonating strike as quickly as possible. The reason why is that sonic wave and resonating strike deal 50+50+10% of current health, and increases damage with each level. This is the same as having a madreds without having one!

(Format of skills: each number represents the skill level, while the parenthesis gives better insight to extra damage output.)

Sonic Wave: Q1

(Active): Lee Sin projects a discordant wave of sound to reveal his enemies for 3 seconds, dealing physical damage to the first enemy it encounters. If Sonic Wave hits, Lee Sin can cast Resonating Strike for the next 3 seconds.

Cost: 50 energy
Range: 975

Physical Damage: 50 / 80 / 110 / 140 / 170 (+1.0 per bonus attack damage)

Resonating Strike: Q2

(Active): Lee Sin dashes to the enemy hit by Sonic Wave, dealing flat damage plus 10% of their missing health as physical damage.

Cost: 30 energy
Range: 1100

Physical Damage: 50 / 80 / 110 / 140 / 170 (+1.0 per bonus attack damage)


Second to level would have to be Tempest/Cripple. This is your slow and it is very helpful in chasing. This ability will aggravate the enemy team as you almost every time are able to chase down the enemy champion before they can get away.

Tempest: E1

Active): Lee Sin smashes the ground sending out a shockwave that deals magic damage and reveals enemy units hit for 4 seconds. If Tempest hits an enemy, Lee Sin can cast Cripple for the next 3 seconds.

Cost: 50 energy
Cooldown: 10 seconds
Radius of AoE: 350

Magic Damage: 60 / 95 / 130 / 165 / 200 (+1.0 per bonus attack damage)

Cripple: E2

(Active): Lee Sin cripples nearby enemies revealed by Tempest for 4 seconds, reducing their Movement and Attack Speed by 30/37.5/45/52.5/60%. Movement and Attack Speed recover gradually over the duration.

Cost: 30 energy

Radius of AoE: 350

Initial Slow: 30 / 37.5 / 45 / 52.5 / 60 %


Third to level is safeguard/iron will, because it allows you to escape champions chasing you and with a resonating strike get back into the action. However, do not go back in if your health is below 30% health! The only circumstance in which this works is if the enemy has under 30% as well.

Safeguard: W1

(Active): Lee Sin rushes towards a target ally, shielding them both from damage for the next 5 seconds. After using Safeguard, Lee Sin can cast Iron Will for the next 3 seconds.

Cost: 50 energy
Cooldown: 8 seconds
Range: 750

Shield Strength: 40 / 80 / 120 / 160 / 200 (+0.8 per ability power)

Iron Will: W2

(Active): Lee Sin's intense training allows him to thrive in battle. For 5 seconds, Lee Sin gains lifesteal, spell vamp, and armor.

Cost: 30 energy

Spell Vamp & Lifesteal Bonus: 5 / 10 / 15 / 20 / 25 %

Armor Bonus: 10 / 15 / 20 / 25 / 30

The last and most prioritized has to be Lee Sin's ult.

Dragon's Rage: R

(Active): Lee Sin performs a powerful roundhouse kick launching his target back, dealing physical damage to the target and any enemies they collide with. Enemies the target collides with are knocked into the air for a short duration.

No cost
Range: 375
Knockback distance: 1,200 (estimate).

Cooldown: 90 / 75 / 60 seconds

Physical Damage: 200 / 400 / 600 (+2.0 per bonus attack damage)

Skill order: R->Q->E->W (In order of priority.)

Feel free to modify the skill order based on game conditions and your play style.

The above information is valid as of 8-19-2011 from League of Legends wiki website.
http://leagueoflegends.wikia.com/wiki/Lee_Sin_the_Blind_Monk

Feel free to give me feedback and make this guide better.

Also this is my first guide, so if it's not up to par the other builds right now sorry. It is almost midnight and I am tired. Will work on making it more professional soon.