AP. AD is nice early on, but you quickly realize that your one spell doing nice damage doesn't match up to all 4 doing nice damage, especially when you wind up with a Lichbane.
After playing Ezreal for 50+ games... AD is much better as a carry. AP might be more versatile, but AD lets you dominate. The problem is AD takes more skill, as you are reliant on a skill shot that does not go through minions, unlike AP. Also, AD provides added survivability as you have the option to take a plethora of life steal items which are vastly superior to the magic vamp items. Also ap is too item reliant, with you starting out way too weak. The ad route allows for quicker kills, and don't forget your passive, with 5 stacks, the speed increase for free makea you a best. Don't forget your atto attack hits like a beast as ad.
Don't know if it was a fluke or the other team was just that bad but in my first game ever as playing ezreal I played him as AP and went 24-6-20. AP Ez sure is doing something right.
man this guy has really really been eatin the nerf burger a lot - i think AD is the only way to go with him now just so you're not basically useless for the first 11 levels. i dunno if i wanna spend 6300 ip on him anymore