the k501 is a discontinued model, wich means people looking to buy them will be looking at prices around $200.
im still going to press the idea that you at least go to a store and test a pair of ultrasones, the offset drivers offer an amazing effect, instead of fusing your head with a soundstage, the ultrasones put the soundstage around you.
Ultrasones Offset Drivers offer safer listening by not biraging the eardrum with pressure changes directly, and ported sound allows your outer ear to feel the music as well, wich dramaitally broadens and expends on the soundstage. It basically feels like im listening to a row of JBL LSR series studio monitors.
we have a pair of AKG k701's and a pair of K601's in our studio for producers that rent out from us. along with them we have 3 pairs of ultrasones. proline 750's, 2500ULE's and HFI 700's, the pair of k701's have been used by only one producer, and that was a girl. our most used pair is the closed back proline 750's. 2 of our event DJ's have ultrasone DJ1 pro cans. wich they decided to buy after mixing in the studio with the proline 750's.
hell, even i baught a pair of proline 750's after hearing them, and i was saving my pennies for the K701's. these arent loud cans, they dont have the best EQ curve i have ever seen, but they do offer a very natural feeling sound, its like being put in the environment where the recording was done(depending on the quality of the recording - hence: i only listen to well produced music).
i admit, a pair of headphones can sound too good. to the point where they bring out the flaws in recording and production.