#1
im left handed and im lookin for under 600 bucks.

schecter c1

epiphone sg g400, then throw some new pickups on it.

or a ibanez rg370dx???

i like metallica, iron maiden, led zepellin, so essentially i want versatility in this guitar without sacrificing on the metal/heavier end.
#2
maybe a HSS or HSH ibanez and put a high output dimarzio in the bridge?
(Main)Gear-v
Jackson Dinky DKMGT
PRS SE Paul Allender
Peavey 6505+ 112
#4
I'd say the Schecter for the reason that you won't need to mess with the Floyd Rose to tune to D or to install new strings. My second guitar was (still have it, though I'm trying to sell it) an Ibanez RG470 and I absolutely hate the Floyd Rose since I can't drop-D. So the Schecter might be a better option (better than the Epi since you have higher reach as well).

Another nice guitar is the Explorer, you might find a Faded used for that price.

Alternatively, look into www.rondomusic.com. You might get a really nice guitar from there for lower budget, and these guitars are good quality pieces and very cheap (due to off-shore labor). The extra $$$ you might be able to use for really good Seymour Duncans (Jazz/JB set preferably)