I love metal...especially the old 80's metal as you said slayer/antrax/testament i never really got into metallica and have never heard celticfrost.....i also adore pink floyd...
if your looking for somthing new(ish) to listen to, i strongly suggest you check out strapping young lad....their "city" album is the best imo (they are heavy and pretty brutal)
im going to check out a perfect murder now....ill let you know what i think
cheers