So, I just bought Olaf a few days ago and wow. He's amazing at doing his job, which is to kick ***. He's uber tanky and only gets stronger the tankier he gets. Basically, this guide will make people rage. Plus, I think he's getting a buff soon! :D

Armor pen. marks because these synergize well with his ult's passive. Your dps will be massive with your W.

Armor/lvl seals because these make him tankier late game when facing hard hitting carries.

MR/lvl glyphs because any AP carries burst hurts like f*ck. Until now.

Flat health quints because they make your W more powerful during early game laning. And staying in lane is what Olaf loves doing.

Olaf is best played as a tanky dps, and with this guide he can do exactly that. I take 9/21/0, making sure to get armor pen before the 21 if you aren't level 30 yet. I also take health and health/5 masteries so Olaf is tanky enough to lane until you chose to leave. I take movement speed over CDR because people say he's too slow and has poor chase, but not with these + FoN + Phantom Dancers.

Doran's sheild is a great item to lane with, and it gives W more damage than Doran's blade does. Berserker Greaves go well with his passive, and they make those 6 seconds of W count. Phage and eventually Frozen Mallet is Olaf's item. It makes him tankier, stronger, and makes his chase 1337. I sneak vamp scepter in there so that i can 1v1 people better and heal up faster between fights. I sell it eventually, however. Warmogs makes Olaf a super tank before anyone realizes it. He takes massive beatings, only to turn around and dish out massive damage with W. Atma's Impaler just makes his damage fly through the roof, plus armor and crit chance are always welcome. FoN is my favorite MR item. At 76 MR, its the best item, and since we only get 1 MR item, might as well be the best. It's movement speed bonus will let us chase down Dat Ashe thinkin she can get away. And the health regen is massive when you have 4k health. Finally, Phantom Dancers puts out more DPS than a ***** puts out on dollar day. Best way to finish. Then, get any/all the pots you want!

Basically, this build will rock face. The massive damage and heal from W and the true damage from E turns you into a Tiger Tank. And no one liked fighting those very much.