A lot of people think you can't play ezreal ap, they are wrong he is a very good burster. High damage ult that goes across map and has low cool-down. This is mainly a item build and your spell sequence and bursting sequence. AP ezreal is best to go mid but he can go bot.

<IMG>http://edge1.mobafire.com/images/item/lich-bane.gif</IMG> is a must because of the passive it also allows the on hit feature of mystic shot so it can do a lot of damage after using one of your spells. I choose[*]deathfire grasp over [*]morello's evil tome because of the active of it can hurt a tank quite a bit and it is worth the 5percent cdr. Ezreal has no stun or slow so getting a [*]rylai's crystal scepter is a great item. I like getting an [*] archangel's staff so that you can spam spells also besides the rabadon it will give you the most ap in the game if you get the passive up and he needs plenty ap in order to do a lot of damage. I choose cdr boots so you can use ur spells more often but sorcerer's shoe's are good also. Void staff is also another good choice for any ap.

Essence flux is the spell you max out first as it is very power full and goes throw minions great harrasing tool

Arcane shift is the spell you will max out second because of the better scaling then [*] mystic shot and base damage

mystic shot you pick up at level 4 for the cool down on other spells also it scales 1 to 1 on attack damage so it is more power full the basic attacks

True shot barrage is your ult it is great for minions waves, towers, nuking, or catching a running enemy we get this when we can 6/11/16

Farming is the tricky thing with ezreal he doesn't have any aoe abilities so you need to last hit minions and use mystic shot when ever.

Pro's Con's
Low cool down ult One of his two main damaging spells is hard to hit with minions Cross the map ult Mystic shot doesn't scale very well
built in teleport Not a great farmer
great harrass
Mystic shot does on hit effect(lich bane)

For masteries I choose a point in attack damage and two in butcher so that he can farm a little bit better. I also choose movement speed so you can have a little bit as you will not be getting your boots for a little bit.

I choose glyph's and quints of potency so you have early game damage. marks of insight for some penetration and cdr seal's so you nearly have 40 percent cdr.

I like to use [*] flash because you will be using [*] arcane shift for damage. I also use [*] ignite for more damage or people that flash away or run. Other spells that might be useful are [*] cleanse incase you get stunned ghost since you have a build in teleport [*] heal is always nice so you can bait and want not or get targeted in team fights.

Mystic shot is a very unique skill as it does on hit so if you have your [*] lich bane and you use your [*] essence flux is will activate the [*] lich bane effect and when you use [*] mystic shot it will deal the base damage, one to one attack damage, 20 percent of your ap and 100 percent of your AP.