[Mag]

  If you listen to Hard Rock or Heavy Metal music you know that Riffs are what make or break songs. You're probably familiar with great Riff makers like Jimmy Page from Led Zeppelin or Toni Iommi of Black Sabbath, but there are many more other catchy Riffs.

I'll start 'er off with Porcupine Tree- Fear of a Blank Planet.
https://www.youtube.com/watch?v=XDrKkuEgFG8

[Mag]

Let's continue with Porcupine Tree- Halo
https://www.youtube.com/watch?v=J_aXs4O9JoQ

[Mag]

Rainbow- Black Masquerade
https://www.youtube.com/watch?v=rqB9Qimd9Wo

[Mag]

Sons of Apollo- Opus Maximus

https://www.youtube.com/watch?v=E8UpiN31_EA

[Mag]

Black Sabbath- God is Dead

https://www.youtube.com/watch?v=49ygxQVSyWk

[Mag]

Japanese Girl Metal, I told you rock was in good hands.
Lovebites- Holy War

https://www.youtube.com/watch?v=bgAxpEpEcno

[Mag]

More Girl Metal 
Lovebites- We the United

https://www.youtube.com/watch?v=UnNxvgLI_Rg

[Mag]

Do you want some more? Than show me
Lovebites- Break the Wall and Shadwmaker

https://www.youtube.com/watch?v=OnhwV9_LbWk

[nlitworld]

You can't have a "Famous All-Time Riff" list without Slayer - Raining Blood. That entire song is iconic, but that starting riff is absolutely legendary.

Raining Blood

[ArthurDent]

Ok, not sure it qualifies as a "riff", but have always considered it an iconic piece -  Lou Reed: Rock 'n Roll Animal's Intro to Sweet Jane. Written & performed by Steve Hunter.

  https://www.youtube.com/watch?v=KqpWTC-rvhQ

[BCRich1]

Maybe it’s considered an Intro, but one of my fav’s. I’d add John Cougar’s I Need a Lover to the great intro list.

[Mag]

Band-Maid: Hate
These ladies know how to Rock!

https://www.youtube.com/watch?v=yfORoQIqB3E