What bands/songs inspired these songs?

So, Avenged Sevenfold's latest album, Hail To The King, was meant to be kind of a "tribute" album to all of the bands who inspired them and, apparently, each song is kind of a reference to a particular song by one of their influences. The "This Means War"/"Sad But True" connection is obvious, someone on YouTube pointed out the opening of "Shepherd Of Fire" being similar to Megadeth's "Trust", I'm guessing that "Doing Time" was inspired by something from Guns N' Roses. Anyway, though, I don't know much '80s Metal and I'm not really familiar with '70s Metal at all, so could someone who grew up on that music please help me figure out the inspirations for the other songs, mainly my two favorite tracks, "Requiem" and "Planets"? I love these songs and if the "remakes" are this good, I really need to hear the "originals"...

"Requiem"

http://www.youtube.com/watch?v=FLNeMkNcYmE

"Planets"

http://www.youtube.com/watch?v=m2je7wqKyKQ

I'd appreciate it if someone could also help me with the inspirations for the other songs on the album, "Hail To King", "Crimson Day", "Heretic", "Coming Home" and "Acid Rain", but I really want to know about "Requiem" and "Planets".

BQ: What are your opinions on the album? It seems to be a love it or hate it album with people on one side dismissing it as a "cover" album and thinking it's sad that they got a number one album by basically ripping off of other bands, but people on the other side are glad to see a modern band who know where they come from. I personally love their decision to do a "tribute" album because not only is it a great homage to their influences, but it introduces that music to their younger generation of fans who missed it and makes them want to go out and find the songs that inspired theirs, which seems to be their main intention for the album (it worked for me). What side of the debate are you on? Just curious.