Black Sabbath: Listen to 'Black Sabbath' and 'War Pigs' from Ozzy Osbourne's album 'The Ozzman Cometh'. It is a recording of a Black Sabbath practice session but it sounds extremely scary... I got so freaked out the first time I listened to that track when I was in Class 9... I like the track 'Symptom of Universe' too.
Judas Priest: Their track 'Living After Midnight' is pretty popular.
Poets of the Fall: 'Lift' is worth a listen.
-- My current rig
Guitar: '98 MIJ Ibanez RG520 QS w EMG 81/60
Amp: Laney LC15R Tube, Fernandes 20W SS
Pedals: MI Audio Tube Zone Overdrive, Boss OD3, CS3, MT2, HM2, DS2, CE5, DD7, TU3, Beta Aivin DD2 Delay, Dunlop Crybaby 95Q, Stranger Vol Pedal, BBE SupaCharger
Others: Yamaha RBX 374 Bass, Yamaha MM-6 Synth, M-Audio Fast Track, Shure SM-57, Heet Sound E-Bow Plus
Wanted(pm if selling): EB VPJr/Boss FV500L,Ibanez w Original/Lo-Pro Edge