Feed Me-One Click Headshot Skrillex-Scary Monsters Nice Sprites Rob Zombie-Sick Bubblegum The Beatles-Come Together Metallica-Nothing Else Matters Halestorm-Love Bites(So Do I) Three Days Grace-Never To Late Slipknot-Before I Forget Shadows Fall-The Light That Blinds Etc.
For me, there's one "best song ever" for everything. Best theme song, best classic rock song, best Danny Elfman song, best Judy Garland song, best song from each movie, best Michael Jackson song, best Disney song, etc. :)
My answer to this question changes frequently.. so... I'll go with what I'm feeling into right now "Vermilion pt. 1" by Slipknot, "PsychoSocial" by Slipknot, "Spirit Ditch" - Sparklehorse, "House of Cards"-Radiohead.
Dance with the Devil - Breaking Benjamin Dear Agony - Breaking Benjamin Perfect Weapon - Black Veil Brides I Write Sins Not Tragedies - Panic at the Disco Hero - Skillet Across the Line - Linkin Park This is War - 30 Seconds to Mars Hurricane - 30 Seconds to Mars In the End - Black Veil Brides My Songs Know What You Did in the Dark - Fallout Boy