I may be sick in some way:
Owned and sold many times more than this.
definitely a horder...
Pioneer SE-300 ans SE305 (just out of curiosity, costed nearly nothing, not used)
Koss KSC35 and 2 pairs of KSC75 (have gotten lots of usage in the past)
Jays V-Jays (somewhat similar to Koss thingies)
AKG K518 (modified, still not great)
Fostex T50RP both modified and EQ'ed (have not been used for years, great sound though)
Beyerdynamic DT990-600 (oldie, used it for many years, not used any more but can't part with it)
Beyerdynamic DT1350 EQ'ed and nubuck pads (used these on vacation now and then, need EQ, very dynamic and good SQ to me)
HD250-Lin II (2 of them, not in use one driver defective)
HD238 (modified, wife uses it on vacation)
HD438 (modified, not in use any more)
Philips Uptown 2x (modified, good SQ, not in use anymore)
Mitchell & Johnson JP1-DJ (not in use)
Master & Dynamic MH40 stock (+ passive filter) not in use.
Superlux: HD681 (modified), HD681-EVO (modified), HD662-EVO (modified) HD687 proto (modified), HD688 proto (modified), HD671 proto + production (modified), HD672 proto + production (modified)
Fostex TH-X00 (used with EQ, rarely used)
Sennheiser HD58X proto + HD58X production (modified and filtered) occasionally used
Sennheiser HD650 (old, black driver) (EQ'ed) has been used extensively in the past. Now in the drawer. Not gonna sell it.
Beyerdynamic Custom One Pro (modified), my current toy. Did not like the stock version.
Sennheiser HD800 (EQ'ed).
Favorites: HD800 (EQ'ed), HD688 Proto (modified), the production version is not nearly as good, DT1350 (EQ'ed), KSC35, HD650 (EQ'ed), COP (modified), HD58X (modified and filtered)
Most usage: HD800 (EQ'ed), HD688 (modified proto) and currently new toy; modified Beyer COP.