Goldring headphones. Either NS1000's or DR150's. Great headphones. You could spend £100 on a headset, that wouldn't sound as good. In fact I'd wager even Sennheiser's PC360 headset at £150+ wouldn't sound as good. Anyway, both cost a mere £50. There have been a lot of threads on both headphones, and many positive comments from people who have bought either headphones, after recommendations from many happy users, inc me.
What Hi-Fii have reviews of both, so you can go read up about them, if you want to see a more professional review.