The D5000's are the best all-arounder I've heard. Their sound signature is warm (but not colored), natural, easy, detailed (but not hyped or analytical), upfront (but not in your face), unfatiguing, reasonably vivid, very smooth, pure, well-balanced (except they can be bass heavy with some types of music and amps).
Mids: There is something about the D5000's tonality in the mids that just hits it right. Other phones like the K1000's and Stax are a bit more resolving in this area, but lack a certain sense of purity, ease and musicality in this region that the D5000 have. Compared to the other phones that you mentioned the D5000 is arguably more natural here. For me, the mids are almost everything in jugding a phone - it's where most of the music lies.
Highs: Slightly rolled off, a bit sweet, but still very convincing and real.
Bass: This is the area that can be troublesome. the bass is huge and deep, but a bit flabby and overpowering with some music. IMO,the markl mods correct at least 75% of the problem (Do a Headfi search). Once corrected, the bass is way better than the other phones you mention.
Soundstage: Similar to the RS-1's in their unmodded state, meaning a bit flat, but very intimate. A slight ear pad mod (markl version) will open up the soudstage to near perfection.
I hope this helps.