what are the best songs in the styles of rock, metal, screamo, heavy metal?

Rock - AC/DC - Back in Black
Metal - Motley Crue - Dr. Feelgood
Heavy Metal - Metallica - pretty much anything off the first three albums

Screamo - ? I'm not much into screaming so will leave this to others.

You should listen to some of the new Norma Jean, Underoath, Atreyu, Metallica... those should satisfy

I absolutely agree with your "Stairway" assessment!!
Try: Dope "die mother f**ker die"
Mudvayne "Determine"
SOD "Season the obese"
Hell yeah "Hell yeah
Anything by Five Finger Death Punch
Anything by Hatebreed
Anything by Bullet FMV
Also check out the old school stuff; WASP, Accept, Dark Angel, Testament. Happy Metal hunting to you!

I absolutely agree with your "Stairway" assessment!!
Try: Dope "die mother f**ker die"
Mudvayne "Determine"
SOD "Season the obese"
Hell yeah "Hell yeah
Anything by Five Finger Death Punch
Anything by Hatebreed
Anything by Bullet FMV
Also check out the old school stuff; WASP, Accept, Dark Angel, Testament. Happy Metal hunting to you!