The standard S4 build for Ezreal tends to fall off late game, which is the most essential part of any solo-queue game. This guide emphasizes attack speed and critical strike with a phantom dancer, berzerk's, and an infinity edge. Try it out in a normal to see how op it really is. A bloodthirster is nice, but unnecessary. In many cases a blade of the ruined king will do more damage than a bloodthirster, because of BoRK's passive. A last whisper is nice, but falls off a wee bit late game. The ideal build would be Berzerks w/ furor, tri-force, infinity edge, phantom dancer, BoRK, Bloodthrister/defensive item.

You'll be behind without a doran's blade. Two might even be necessary.

Buy sheen if you have been lucky in hitting your q's.
Buying a phage is pretty standard after first back, but you may also need a second dorans blade. Only get BF Sword if fed.

These items are pretty standard for an AD Carry Ez.
In many cases, buying a BoRK will do more damage than the BloodyT. Tri, Berzerk's and IE are irreplacable.

Last whisper should be incorporated into your build somewhere. Only get GA if their AP can get to you. Get Omen in all other cases. Furor is essential.

Although it is tempting to get CDR, as an adc you need attack speed. It makes a huge difference late game. The block mastery is nice for winning trades, and the Meditation one is great all game long. Feast increases sustain decently, but can be substituted.

Max q. I take one point in w at level 4, just to get some sheen procs in lane. It will hurt late game, however.