What is a great metal guitar?

I allready have one guitar, which is an Ibanez SA36. A great guitar,
but it only has one humbucker. Also, I really like the thinner necks
Ibanez have. So in general I'm looking for a second guitar which is
really made for metal, and distortion. I'm looking towards the brands
like ESP, or Jackson. However I wouldn't mind another Ibanez, for
example the RGA series looks good... My price range is about $250-600.

So which guitars would you suggest?