In cronological order
PX200 - Amazed me as my first non stock headphones
PX100 - Loved the bass against the 200
HD595 - These were my first real full size love, to date I still have a good opinion of them
K701 - Found them cheap and thought they were amazing value, unfortunately I didn't like them so sold
them shortly after
AD700 - They were mentioned as great for gaming, didn't like them due to no bass so gave them to a friend.
HD650 - Loved the overall improvement over the 595, but after a while I realized that I preferred the frequency response of the 595, but they are still in my collection for bright or compressed music and podcasts/youtube
HD800 - My reference, I love them and they will be my main headphone for the foreseeable future
PX200-II - Needed something closed and compact for traveling, and like them better than the PX100
DT48S - These are a 50's headphone, wanted to try a vintage headphone, and they were regarded as being something different than modern headphones like the K1K or HD800. Love them and probably I'll get another DT48 in the future since it is cheap.