As anyone that has kept up with the comments section of the HBB Blog surely knows, Deicide obliterated As I Lay Dying in last week's good vs. evil edition of Who Rocks Harder? Later, we'll feature a block by Glen Benton and Co. to celebrate the slaughter. But for now, we've got a more traditional match up for you -- Metallica Vs. Megadeth -- a heavy metal rivalry to equal Tupac Vs. Biggie (only without the drive-by shootings).

In their prime (1983 - 1991), Metallica were untouchable. The band pioneered thrash in an era of hair metal, then rose to the top of the heavy metal hierarchy through a combination of stellar songwriting, uncompromising perseverance and incredible live shows. 1983's Kill 'Em All was a landmark recording, combining the metallic edge of Judas Priest and other groups from the new wave of British heavy metal with the speed and aggression of hardcore. It didn't just raise the bar for metal, it forged the furnace for thrash, and without it, Slayer, Exodus and Anthrax might have had entirely different sounds.

In fact, Metallica first four albums feature some of the best and most influential metal ever recorded, and their fifth record, 1991's far more commercial "Black Album," sold over 14 million copies, making it one of the most popular rock albums of all time.

It would be pretty near impossible to top that, so Metallica didn't even try. Instead, they headed off in new sonic directions. And while the metal world hasn't universally praised 1996's more experimental and groove-saturated Load or 1997's similarly structured Reload -- not to mention the largely reviled 2003 album St. Anger, Metallica still destroy live, and many fans are hopeful that the band's next record will be a return to their former glory.

Few metal bands can compete with Metallica in terms of global popularity, however when it comes to metallic cred Megadeth certainly have a shot. In part, that's because Metallica and Megadeth started in the same place -- literally. As everyone knows, Megadeth frontman Dave Mustaine was a co-founder of Metallica, but was booted from the band for being a belligerent drunk before Metallica recorded their 1983 debut Kill 'Em All.

In less than two years, Mustaine bounced back and released the first album by his new band Megadeth, Killing is my Business... And Business is Good. The album was jazzy and technical, and established Mustaine as more than "the guy who was booted from Metallica." Megadeth's 1986 follow-up, Peace Sells... But Who's Buying? was even more impressive -- simultaneously catchier and heavier without being less complex. It's this musical proficiency and commercial appeal that propelled Megadeth through their next three albums, culminating with 1992's Countdown to Extinction.

But around the same time as Metallica were struggling to find a new creative path, Megadeth made some similarly questionable career moves. Striving for a broader audience, the band started writing poppier, less challenging tunes that paled in power to their earlier output. The band's St. Anger. was 1999's Risk, which, in an effort to keep up with the times, featured an abundance of misguided electronic and alternative rock arrangements. But while Metallica haven't yet bounced back in the eyes of many metalheads, Megadeth have clearly made amends for their past, cranking out a succession of increasingly thrashy post-Risk albums that culminated with 2007's United Abominations.

Place your vote in the comments box bellow. This could be a close one.

The winner of last week's Who Rocks Harder was Pantera, who beat Slayer by an overwhelming majority.This week, we've got a more theological contest -- a battle of good and evil that's demonstrates the full range of independent metal. The first band is As I Lay Dying, the Christian metal group that won the "Ultimate Metal God" award in MTV2's All That Rocks contest in 2006. They're up against Deicide, the pioneering death metal band whose frontman, Glen Benton, deplores Christianity and once branded an inverted cross in his forehead.

The videos are As I Lay Dying's "Nothing Left" (shown above) which was directed by Brian Thompson and Deicide's "Homage For Satan" (displayed below), directed by Alfred Tomaszewski and Matthew Stawski. Place your votes in the comment box below or burn in hell for all eternity. Remember, judge by band, not by video. Also, watch Deicide's "Homage for Satan" again on this weekend's Halloween episode of Headbangers Ball on MTV2.

Two of the heaviest, most inspirational thrash bands go at it in the second week of our Who Rocks Harder challenge. Last week's winner, by the way, was Judas Priest, who beat out Iron Maiden by a slim margin.

The influence of both Slayer and Pantera extends far beyond the boundaries of thrash. Slayer burst onto the scene with hardcore beats and razor-honed riffs that were so brutal they left most everyone in the dust. Combined with vivid controversial lyrics about their favorite subjects -- Satan, serial killers and war -- they paved the way for crossover and death metal. And while they may have hit their peak before 1990 with the albums Reign in Blood (1986), South of Heaven (1988) and Seasons in the Abyss (1990), they've delivered consistently vicious stuff throughout their entire career. Even during the grunge and alternative eras, Slayer never wavered from their distinctive style of bludgeoning. Plus, they get bonus points for having one of the sickest drummers in metal, Dave Lombardo, whose tumbling, precise beats propel the bad-ass songs.

If Slayer are the Beatles of metal, Pantera are surely the Rolling Stones. Okay, in their youth the band started on a misguided rocket ride of commercial/glam metal, but they more than made up for it after acquiring vocalist Philip Anselmo and releasing their explosive fifth album, Cowboy From Hell, in 1990. From there, Pantera quickly proved their mettle with album after album of southern-groove flavored hate-thrash that was shy of neither aggression or attitude. All the guys could play and Anselmo's vocals were absolutely vita -- a key influence on the emergence of metalcore -- but group's greatest weapon was guitarist Dimebag Darrell, who brought proficiency, power and feeling to the band with both his crafty, gritty rhythms and his jaw-dropping leads.

Watch the two vids, then vote for your favorite below.

Here's an argument metal fans have been having for decades. Who rocks harder, Judas Priest or Iron Maiden?

Obviously both bands are legends, and each has its debate points. Judas Priest pre-dated Maiden by about six years and was the second most popular metal band in the early '70s behind Black Sabbath. The band's dual guitar sound and leather and studs attire ushered in the new wave of British Heavy metal movement, of which Iron Maiden also played a major role. Also, Priest's songwriting throughout the glory days of metal was untouchable: "Screaming For Vengeance," "Breaking the Law," "Living After Midnight" and "Some Heads are Gonna Roll" are just a handful of their legendary hits, and each achieved notoriety without relying on power ballad constructions or watered down production. And let's not forget vocalist Rob Halford, whose multi-octave, vibrato-laden voice is so powerful, he's widely called the "Metal God."

As for Maiden, their longtime singer is no slouch, either. Although he didn't join the band until 1982, Bruce Dickinson solidified Maiden's attack with mighty vocals that were part operatic croon, part banshee howl. Over the years, Maiden, too, have composed some of the most captivating songs in metal. Their galloping rhythms and sinuous guitar harmonies pioneered power metal and their stellar arrangements combined complex musicianship with timeless hooks on songs like "The Trooper," "Number of the Beast," "Aces High," "Flight of Icarus," and "2 Minutes to Midnight." Also, Maiden brought the world the most recognizable mascot in metal, the immortal zombie, Eddie. Now you guys duke it out. Leave your comments below. And look for more bar room argument topics in the weeks ahead: