The major strength of HP-1000s is that it reflects the sound of the source/amp as accurately as any headphones that I have heard. It is clear window to what it's connected to. Garbage in, garbage out. Connect it with good cables, good amp, and good source, and you're in heaven. The HP-1000s are 40 ohm by the way.
Voices/musical instruments are rendered as accurately as possible with the HP-1000s - other headphones, i.e. R-10s & RS-1s add coloration that some may like, but it isn't my cup of tea. This coloration becomes bothersome to me because the signal coming from the source already reflects a fairly accurate portrayal of the sound of a violin, and the extra woodiness that the wood ear-pieced headphones add becomes an unwelcome coloration.
I guess I differentiate headphones and speakers - I don't look for the same sound in headphones as I do for speakers. The strength of headphones is the quickness and PRAT. Speakers soundstage and image much better than headphones IMHO, so although I look for these qualities in headphones, they are not the consuming priorities.
Musicality in the HP-1000s doesn't come from the headphones, but if your source sounds good, the HP-1000s are the last limiting factor. Not many headphones can claim this.