Interesting....I think we'll see that loudness is relative to the listener - I prefer comfortably loud (as in cant hear the wife or tv), but not bleeding ears 
However, for what its worth:
I always send at 4 blocks short of max - BUT - I don't run my iTunes at max volume either. I try to keep everything pretty much at the 60-70% mark, then let my Darkvoice 332 do the work (usually at 9:00 position). I'm on the hunt for a dedicated DAC so I don't have to do this any longer, but for now its what works. My current favorite cans are Beyer DT770Pro 80ohm.
Hope that helps....
H
