Heres my best shot at a review for you
Ok... I'll try a review of reviews...
All sourced by my Marantz CD63se....
First off... HD565 vs HD580
This was done on my QED MB45 (handy... has two outputs) and, well... the HD565s just don't have it... they sound very tinny, and congested compared to the HD580s, also there bass is weaker, less substantial... I can't believe that the HD565s were my favourites, and so well reviewed by hi-fi press for so long, they sound dismal in comparison...
Winner : HD580
HD580 vs CD1700
Hmm... this is a matter of personal preference I feel.. The CD1700s sound meatier... more in your face in the midrange area... and are also duller in the treble area (not sure if this is a good, or bad thing yet... the HD580s seem to "Zing" a shade too much at the moment... will i get used to this... thats the question) Basswise, the HD580s seem to lay the law down... more authorative... deeper
Winner : None... matter of personal opinion, and musical taste
QED MB45 vs X-Cans V2
The QED is cheap and cheerful in comparison to the X-Cans... it has all the fundamentals... solid bass, sparkly treble (not that good a match with the HD580) but a decided lack of midrange...
Also, especially with the CD1700s, the QED hisses like anything... its not enough to disturb the music, but, when there is a quiet passage, it is definetly there, makes the CD sound more like Cassette... although, this isn't (obviously) noticeable on the Senns
With the X-Cans, you can just hear the faintest trace of hiss at low volumes (and... mine, like many others at minimum volume still plays music from the left channel)... but this unit is so much more musical than the QED... A sound that you can fall in love with... EXCEPT... the bottom octave of bass seems to distort on the Sonys (although interestingly hasn't as yet on the HD580s... could be an impedance thing?!)
Winner : X-Cans V2
Its all a matter of budget as to which setup is best... none is "amazingly bad"... just gets better the further up you get
Bargain basement : HD565 & QED MB45 - Treble that you don't normally expect from "mid-fi" along with a quite substantial (although congested) bass and midrange
Total Cost $250
Mid range : HD580 / CD1700 & QED MB45 - much the same as with the HD565s but a lot more definition, with the added midrange of the CD1700s making for a good vocal listen (if you can handle the hiss)
Total Cost $400 (HD580) or $270 (CD1700)
Upper range : HD580 / CD1700 & X-Cans V2 - This is a much more neutral sounding... not such savage treble, smoother, deeper bass, and pristine, perfect (imo) midrange with the HD580s... maybe a bit too syrupy with the CD1700s but, there smoothness in the treble area takes the edge away from the HD580s which can singe your eardrums if you are a bit too keen with the volume control
Total Cost $500 (HD580) or $370 (CD1700)
One interesting thing that has slightly annoyed me... The Senn HD580s seemed slightly dull out of the right channel, I was about to send them straight back, but i decided to swap the driver housing (NOT the backs) over with my HD565s and... voila... the sound is equal as it should be, and the HD565s are now dull on the right hand side... obviously a defect in the moulding of that part....