One word…
Sennheiser
I've been a DJ for over a decade and wouldn't use anything else.
Take a look here for some inspiration
FWIW the 212's and the 215's on that link, at 50 and 60 quid respectively, are very very good, crisp clear sound, loads of bass, highly recommended. Or you can blow 150 quid on a set of HD25's for him (that's what I use, wouldn't change them for ANYTHING!) and he'll thank you for it… Trust me!
Oh, and Skull Candy are poo… All about the looks, which I personally think are trying too hard anyway… If you're wearing a pair of Sennheisers, people who know what they're talking about know you know your stuff!
EDIT: JUST checked the specifics on the Skull Candy phones… 100-18,000Hz frequency response! Pissed myself laughing! That's atrocious… Means you'd get no bass whatsoever! The Sennheiser HD215's at almost the same price have a frequency response of 12-22,000Hz!!! You're not gonna miss ANY bass notes with those bad boys… And if you shop around You can get them for just over £50, which is a veritable bargain I think you'd agree!