The title says it all. If you're not a fan of metal, please don't post here.

Feel free to elaborate as to what makes them the best in your book. I'll start, in no particular order:

Metallica (Kill Em All through AJFA) - do they really even need an explanation? They're Metallica, they are responsible for so much of this genre, it's insane. Wasn't a huge fan of the early 90's stuff though. Black Album was cool

Iron Maiden (Iron Maiden through Somewhere in Time) - Absolutely love Maiden, saw them twice in the same summer! Bruce is my favorite metal frontman - I just love his vocal style, powerful, reaches and connects with the crowd, great range. As a guitar player, i'm a big fan of Adrian Smith as well. In general, I just love how melodic and tasteful their music is.

I dug the earlier punky Paul D'Anna stuff, but that wasn't the Maiden 'sound'. Also hated the Seventh Son stuff (with the exception of 2 songs) and beyond... but those golden years... there was nobody better!

Slayer - For being the most badass thrash band of all time. Angel of Death, for me, is still the quintessential thrash song. Sick riffs and lyrics... Reign in Blood was a brilliant album

Pantera - For bringing the style they did to the genre. Songs like 'Walk' just make me want to hurt people... I love the energy!!!

The last one is a toss up for me because I love so many other bands, and it's tough to narrow it to 5 (maybe I should have done top 10?). I have to give it to Sabbath - they pretty much invented the genre after all. Ozzy is a metal God.

Honorable mentions to:

Testament
Nuclear Assault
Suicidal Tendencies
Megadeth (hate Dave's vocals, but he's a brilliant guitarist)
too many more to get into.

I am not counting bands like Kiss, Bon Jovi, Van Halen, etc - for ME, they don't fit the true metal genre. Zeppelin is one of my all time favorite bands, but I hardly consider them metal.

Your turn