Ive just bought myself a sony x series mp3 player and I already had some sony in ear headphones to use with it, which are fairly decent. Im considering upgrading the headphones to some larger over the head headphones (as long as they aren't too big). Ive actually got my eye on the Denon AH-D1001's. Can anyone recommend any good headphones over (or even less) than £100? Is this likely to be a worthwhile upgrade for me?. Thanks. Alex.