I'll be revising this as I play with the new masteries.

This is a Zed Exploration guide. Please feel free to comment your questions and advice!

My runes make Zed a tanky assassin, essentially ignoring enemy armor, while holding enough of my own defenses. My attack damage comes from my items, it's easier to build damage than armor pen, so I rely heavily on armor pen runes. If I need to explain more, let me know.

I chose mastery points that make Zed hit even harder. SHREDDING through enemy armor is the focal point.

Youmuu's Ghostblade is a great item for him, giving you a nice attack speed boost to deal extra damage for your ult. Penetrate's more armor, gives cdr, crit chance, and attack damage. A well rounded item to start with. Focus on getting Avarice Blade first to make the rest of it easier. I generally start the game with Brawler's Gloves and two health pots.

Cooldown Reduction is a must for him, but I can see replacing these with Ninja Tabi or Beserker's Grieves.

Dat Slow. Be sticky.

Infinity Edge gives a huge attack damage boost, as well as it's crit chance stats.

Lifesteal + Attack Damage

Ionic Spark gives extra attack speed and health, plus the quarterly shock damage. A nice item that should help you be even more assassin like.

I'll probably find myself using ghost and teleport for the super mobility, though teleport can easily be swapped for Ignite to compliment his ult and deal even greater damage.
I often find myself able to walk away even before a target is dead, avoiding further damage, and still getting the kill as they die trying to run away.

Don't be too impressed, it's just custom bots.