This is the build I made after that crazy 155ap hat came out. If you are having trouble late game with lots of cc on the other team, u might want to buy a banshee's veil first in place of the 2nd hat. Usually I don't get to build anymore caps after the first one, geting those big rods just makes your shunpo a beast, and the rods are really cheap for the ap that you get out of them. It says 700ap at lv18 but the 30% you get from the cap is missing. Total with the 30% bonus should be 910 AP :D Another thing, with just getting needlessly large rods, if you need more defense later on, you can always turn one of them into a zhonya's hourglass.

Pure ult dmg build, the magic pen. marks for more damage. You have very little hp so the hp seals gives you a boost later on in the game with the extra close to 200hp. And you want to use your ult as soon as possible after killing people so the glyphs and quintessence are great for cooldown reduction. Sometimes I can kill 2 guys and have my ult ready in under 5 seconds. Without the cdr runes it would take a lot longer, like 15seconds + still. Oh yea, being able to shunpo again helps a lot, its like a huge nuke!