As the decade comes to a close, 2009 wraps it up in strong fashion. Most of the bands in this year's top 20 have been plying their trade for a while, with a few younger bands cracking the countdown. This list was compiled using submissions from all the About.com Heavy Metal writers, then tabulating the results using a complex formula involving differential equations, quantum physics, calculus, thermodynamics and of course plenty of beer. Here are our choices for the top 20 metal albums of 2009.

1. Mastodon - 'Crack The Skye' (Reprise)

For the second album in a row, Mastodon take the number one slot for the year. Crack The Skye is more polished than their past albums, but their traditional experimentation and quirkiness is fully intact. The band always opens strong, and "Oblivion" is no exception. Mastodon's skills are pushed to the limit on "The Czar," an 11 minute epic with layers of keyboards, and guitars that are sometimes funky, other times very technical.

The vocals are mostly melodic singing, with less screaming than ever. Mastodon also add some vocal harmonies, which is one of the elements that makes it more polished and accessible. While the metal is tempered with classic rock and prog elements, Crack The Skye is still a challenging album with a lot of depth.More »

2. Nile - 'Those Whom The Gods Detest' (Nuclear Blast)

Those Whom The Gods Detest is a career landmark packed with mind-boggling guitar riffs and solos, nonstop speed, George Kollias’ inimitable drumming and a sense of urgency some claimed was missing from their last effort. Death metal bands take note – Nile are back with a vengeance, much like Boris Karloff in the old Universal Mummy pictures.

This album is way past anything on the predecessor. It takes the best elements of classics like Amongst the Catacombs of Nephren-Ka and Annihilation of the Wicked then goes a level further. The solos are breathtaking, the vocal performances are the best ever on a Nile album and Middle Eastern instruments add depth and texture.More »

3. Sunn O))) - 'Monoliths and Dimensions' (Southern Lord)

What makes their seventh album Monoliths and Dimensions so powerful is that Sunn O))) have widened their musical palate and tapped into a new mix of sounds without sacrificing their black-hole bass and sonic rhythms. It’s the best album of Sunn O)))’s decade-plus career and a testament to the limitless potential of the metal genre.

The first track “Aghartha” opens with the traditional Sunn O))) bass chorus before adding violins, a conch shell, English horn and piano. “Big Church” nudges the darkness aside for a mesmerizing female choir and church bells. These touches aren’t curious asides; they are expertly woven into the tapestry of each piece to create a more diverse whole.More »

4. Napalm Death - 'Time Waits For No Slave' (Century Media)

Napalm Death have no inclination to rest on past accomplishments. The British grind legends' 13th album Time Waits For No Slave is another incendiary blast from a band that appears hell-bent on topping themselves with each new release.

There aren't any duds to speak of in Napalm's catalog, but this is an album that will stand with their career highlights. There's so much going on in these songs that the album transcends the grindcore label. Barney Greenway's screams are as vitriolic as ever; Mitch Harris and Shane Embury continue to mine influences from outside metal to sharpen their sound and drummer Danny Herrera offers a performance just short of outright barbarism.More »

5. Baroness - 'Blue Record' (Relapse)

On Baroness' sophomore full-length Blue Record, their sludgy guitars are intact, but explore a bit more of their progressive and experimental side. It's also the first album with new guitarist Pete Adams. Their sound has been compared to Mastodon, and on songs like “A Horse Called Golgotha” that comparison is apt. It’s heavy, but also complex and catchy.

There are numerous textures, intensities, moods and atmospheres throughout the album, and Baroness change things up on a constant basis. Songs like “The Sweetest Curse” are heavy and reasonably straightforward, while “The Gnashing” has more progressive tendencies. John Baizley’s vocals are unique. They are gruff, but still melodic. They add an interesting flavor to Baroness’ sound.More »

6. Megadeth - 'Endgame' (Roadrunner)

Megadeth’s career arc has been on the rise the past few years, and Endgame cements the legendary thrash band’s current relevancy. Dave Mustaine never seems to run out of riffs or anger, and this album is packed with both. “Dialectic Chaos” kicks off the album, a shredding instrumental setting the stage for what’s to come. What follows are guitar heavy thrash tunes that are unmistakably Megadeth. Songs like “44 Minutes” and “This Day We Fight” are intense, groovy, catchy with multiple guitar solos.

More than a quarter century after their formation, Megadeth are still at the top of their game. Endgame has some old-school moments, but also modern ones. 2007’s United Abominations garnered a lot of critical praise, but Endgame is even better.More »

7. Isis - 'Wavering Radiant' (Ipecac)

Each song on Wavering Radiant has ebbs and flows of intensity and tempo. Heavy and sludgy riffs build up to a near oppressive state, then ease up and transition into a lengthy progressive instrumental section before amping up the intensity once again. The vocals are a combination of growls and melodic singing. Unlike a lot of bands where vocals are constant except for a periodic guitar solo, Aaron Turner will sing a couple lines and then disappear for a couple of minutes or more.

The songs flow together really well, and it is truly an album, not just a collection of songs. Wavering Radiant is one of those albums that's easy to enjoy on the first listen, but with time becomes even better.More »

8. Between The Buried And Me - 'The Great Misdirect' (Victory)

While The Great Misdirect is faced with the tall order of following up massive previous CDs, it’s more than up to the challenge. While it’s true that this album takes a bit to kick in, once it does, the result is almost narcotic: that happy and hazy feeling one gets when faced with pure musical bliss.
Each song here takes so many twists and unexpected turns, you almost feel like you're moving in a million different directions all at once…only in the best possible way. From technical death metal/core, to melodic rock passages to thick, bluesy jams, The Great Misdirect rarely, if ever misfires.More »

9. Slayer - 'World Painted Blood' (Columbia)

World Painted Blood kicks off with the title track. After a short intro, it’s vintage Slayer, with the six minute track featuring the power, intensity and groove the band is famous for, plus a sufficient dose of melody. The whole album hearkens back to Slayer’s glory days, with sparse production and a raw sound. It’s an effective strategy, because the band’s musicianship requires no spit and polish to appreciate.

With songs like “Snuff” and “Hate Worldwide,” shredding solos from Kerry King and Jeff Hanneman are on full display, as the two axemen showcase their guitar prowess. Balls out galloping thrash is the rule of the day on World Painted Blood, but Slayer change things up from time to time for diversity’s sake.More »

10. Brutal Truth - 'Evolution Through Revolution' (Relapse)

Brutal Truth have never been afraid to take risks with their hybrid grind, and they throw caution to the wind on their first studio album in more than a decade. Almost every song on Evolution Through Revolution is packed with disparate elements that in lesser hands would end up on the cutting room floor.

“Sugardaddy” lurches forward with propulsive guitar work; a minute-and-a half later it dovetails into a glorious fist-pumping riff. “Turmoil “ is so fast it appears on the verge of collapsing on itself. “Get A Therapist Spare The World” starts with a funky passage, races to a grinding frenzy, then slows down into a doom lick. Grindcore has just inched forward again on the evolutionary ladder. Welcome back, Brutal Truth.More »