Date:

May 10, 2011: Build Created
Mat 11, 2011: Tweaks with summoner spells

Short and sweet, I won't pretend I'm a ranked all-star because I'm not. This guide is merely how I play Blitzcrank, and of course look for updates as I test out variations on items in the furture.

Runes are fairly simple, magic pen reds are must on any ap character, and especially useful because we want to take mercury treads insted of magic pen boots to give us some more survivability. Mana regen yellows are great because blitz has mana issues, if you want to substitute lich bane for archangel's thats fine too.

And hey, runes are all opinion based. What works for me may not work for you. For example, if you want to keep these items and spam your skills more, insted of magic resist blues, you could use mana regen(not per level) blues. Blitz is important for utilizing your combo, and without enough mana, it's going to be way harder than it has to be.

Masteries are caster related because while yes scaling down defense would be nice, this way you get improved clarity and ghost to help get in/get out and keep track of the enemy team.

Why Clairvoyance???

Theres nothing more that the enemy team hates than being pulled out of the brush into your entire team waiting to crush them. With clairvoyance u can get a clear view of your enemy during team fights and also check objectives like dragon or baron. Ghost of course can be switched out with flash or another spell, but try to limit it to positioning based summoner spells, position is your friend with Blitz. Hey, if your not a fan of clairvoyance(or someone else already has it on your team) please please PLEASE grab clarity. Mana is your friend. Plus it really helps with pushing lategame in sted of fountaining.

EDIT**
After testing the build further, I choose Flash over ghost. There are several reasons for this. First of all, flash is a much more viable skill nowadays, and is much more useful in higher ranked matches as well. Second (and most important), is that Blitz's "W" skill is enough of a ghost in itself, and flash is a much better use of your time and GREAT for positioning in an offensive, or defensive situation.

Skill sequence is pretty self explanitory.

Start with rocket grab, if you snag your target either rocket fist them or static field; following up with whichever you havent used yet. Once again, positioning is your friend, and using overdrive to chase or get into position is an all time MUST. Don't waste any of your skills, they're all uniquely important and in combination cause major damage.

Once again, I will stress the point that positioning is KEY, it really sucks to get grabbed by blitz and you enemies will be wary of such. If you threaten the team enough they'll have to turtle their tower, which opens them up to even more of a chance of catching one in a position you can grab.

Pros:

High burst potential
Screw enemies over caught by your fist
Great asset and an AoE silence hits mages hard

Cons:

If REALLY targeted, you can burn out fast
You are NOT a tank, merely tanky, don't get the two mixed up

This section will come as soon as I begin to try this build in a ranked environment, and of course over time will be updated with news of changes in tactics and items. I'm sure with the addition of the new mechanism of crowd control reduction, that new item paths and strategies will become available shortly.

AP Blitz is not the best farmer, while it is tempting to burn abilites (especially your ultimate), usually you want to conserve them for a more deserving opponent. Also, keep in mind that with mana preservation not only are you ready for your full combo, your shield will have a much larger tolerance for enemy damage if your mana is higher. Remember your combinations and passive are what make your character uniquely Blitzcrank, take advantage of the benefits of having higher mana and try to conserve it as abilities can be somewhat costly on Blitz.

For ceeps, basically follow the farming advice above, as mana conservation is extremely important on Blitz. As far as jungling goes that is up to you. This build is not made for junglers, but with rocket grab, jungling would be nice because you can catch your enemy by suprise from brush.

In Short, this guide focuses on an AP oriented Blitzcrank with high burst potential, and team disruption potential. Make sure to make yourself the most useful possible that you can be. Coordinate with teammates to target the biggest threats, use ghost to get in the middle of the team and cause a massive silence nuke. Use your abilities to the full potential and your team will be stuck retreating.

Final Note:

Please rate and comment only after you have tried the build or also play Blitz. Feel free to shar opinions and build alterations, the whole point of the guide is to improve over time and it will be updated whenever new solutions are found and made possible.
Thanks!