When I first ever heard of Ezreal I was watching some tournament. I saw him and all of his ability's and was like "Huh?, this guy looks cool" Turns out the next week he happened to be free. I used him immediately and loved him. My next 6300 ip went in to buying, and still today he is my main AD Carry, and one of my best AP Carrys. Before we start I also will like to note this is ONE way to play Ez, this is not the best just a way I think works.
why AD ez?
So how does one champ play two roles. Well, Ezreal is a strong AD carry do to the fact that his Mystic Shot Scales on AD, he also has nice range and a passive that gives him more attack speed the more ability's you can land.
For summoner spells i would recommend getting Exhaust and ignite because ezreal has a built in flash his E and if you're good enough and dont need another flash you should run exhaust and ignite but if you feel you are not safe enough run flash and ignite