Thanks to Riots buff (yes buff, not nerf) of Ryze, I present to you a very over powered build that stacks health, mana and ability power.

Pros

Fairly tanky build.
One of the best nukes in the game.

Cons

Mediocre early and mid game, takes a good amount of time to build.
Less effective ultimate.

Runes
Because this build stacks health I devote my runes to aiding this health gain. I use standard magic penetration marks, and flat armor glyphs, seals and quints. I do not use magic resistance because the health I build is naturally resistant to nukes from casters. If you are having trouble midding against an ap carry take some magic resist runes.

Masteries
Like my runes, I devote masteries almost entirely to defense, taking 27 in defense and the remainder as mana.

I start with standard boots / pots. You can also start with mana though Ryze is very slow and you will likely run out of health before mana.