I have a pair of 20+ year old 240M's (600 ohm). I plan on taking them with me to my grave.
I recently built a Millett Starving Student Headphone Amp that drives them very well. With a pair of matched 12AT7 tubes my copy of T. Pinnock directing the English Concert (Handel's Watermusik) sounds phenomenal. I can hear the musicians breathing, fingers moving on strings... a very "live" sound.
I'd like to get my hands on a set of the velour ear pads, but I'm not sure where those can be had in the States at a reasonable price.
The foam separator that goes behind the ear pad and over top of the driver dry rotted on my set as well. I vacuumed the chunks out and cut some pieces of felt to replace them for the time being.
http://www.amazon.com/Handel-Water-Music-George-Frideric/dp/B000001G4Q/ref=sr_1_sc_1?ie=UTF8&qid=1333331827&sr=8-1-spell