In no real particular order. These albums are all great.

1.Black Sabbath - Black Sabbath

2.Black Sabbath - Paranoid

3.Led Zeppelin - Led Zeppelin III

4.Sir Lord Baltimore - Kingdom Come

5.Deep Purple - In Rock

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While the order in each decade is purely personal preference, there are several rules for a song qualifying for the list. First off, the band has to be notable. I'm not going to define what that means, but I'm sure you'd agree all the bands in the list are notable. There are plenty of riffs from obscure bands I'd rather put, but I know my love for Tarby doesn't make him the greatest riff maker of the 21st century. Second, each artist can only appear once in a decade, this is to prevent the best riff makers from hogging the list and adding some variety, showing how metal has changed over time. Decades are measured by when the song was recorded, not released, and when it's unclear the beginning of recording is used. This is mainly because a lot of definitive early metal songs were released in 1970, but recorded in 1969. Third, the song itself has to be notable. Here are things that can qualify as being notable: the song was release as a single, has music video made for it, was released as a single, was the title track for an album (note that Crawl through Knives meets this criteria because it was the original title for Come Clarity, and there is no way in hell Come Clarity is getting best riff of the decade ), is included on a greatest hits compilation album, was nominated for a Grammy or musical award of similar caliber, was included as a track in a notable film or video game, was covered by a notable band, or has a Wikipedia page for some miscellaneous reason. Finally, the song needs to be metal. Misirlou gets the pass despite predating metal as it was probably the single most influential song on the development of metal, and while many of the other songs in the other songs are better classified as hard rock, I can find a source listing them as heavy metal.

1.

2.King Crimson - In The Court Of The Crimson King

3.Black Sabbath - Black Sabbath

4.Iron Butterfly - In-A-Gadda-Da-Vida

5.Deep Purple - In Rock

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1.Rainbow - Rising

2.Iron Maiden - Iron Maiden

3.Metallica - Ride The Lightning

4.Led Zeppelin - Led Zeppelin IV

5.AC/DC - Powerage

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