So which kind of headphones can go with our beloved Walkmans ?

For the past two I have tring to find which type of earphones or headphones can go with our walkmans without using Amps (I know very little about these things ) and to my shock most of the headphones can't be used .Why ?Reason is simple 2.5mW for both (R+L) is too less to power most of the good headphones .

Rant over ............