All the high-gain amps used for "modern metal tone" today tend to sound the same to me, but that's probably because to my ears there is a bland uniformity to the "modern metal" sound in general. You see a lot of replies here that list five or six amps, and I think there's a lot of truth to that because it really doesn't matter which one you pick. You can take any one of them, tweak it a little, and get the same unimaginative, chugging djent sound that you hear everywhere on YouTube these days.
I prefer a more, I dunno, vintage? metal sound. Something with a hard charging Marshall driving the tone. I like lots of juicy upper mids, which is where the electric guitar truly lives as an instrument. Sure, you can add an extra string or two in an attempt to drag the instrument's tessitura down an octave, but I feel that's the bassist's territory, and something about the sonic texture of 56-64 AGW strings on a scale length under 30" just doesn't sound good to my ears no matter what amp you hook it up to.
For a Marshall sound with just enough "modern" bite to sound legit today (IMO), you can't go wrong with a good overdriven JVM OD2 preset.