Earphones or Headphones?

I like headphones better, in general.
Two years ago, I used my Sennheiser HD555 all the time. Then someone thought it was a good idea to steal them (and I agree with that person), a bought a new pair of them. But for some reason, my adapter gets crooked after about 2 hours of usage, so I don't have the energy to use them anylonger. Sad, because the sound was perfect for me.

Instead of buying new adapters twice a day, I use some cheap in ear-phones from Koss. I don't really like to put things into my ears, but nowadays I rarely listen to music anyway.