Don't take this too harsh, this as honest is it can be, not trying to diss you, just helping you! On a side note, I find this particular forum one of the coolest forums around (i'm regular on about 5 forums, daily basis), people are really cool and helpful :wink:
Did you by any chance have a CRT monitor turned on near the amp/guitar? Cause that hiss sounds similar to that...
The tone is..well, thin... i don't know how much you know about micing, but try putting the mic as close to the grille as possible (especially if the amp is not turned loud), somewhere around the center of the cone..
And also, the second riff in Enter Sandman should go:
G - E - F# - E - F# - G - F# - E
and you play it:
G - E - G - E - F# - G - F# - E