Here are some ideas.
If your friend does not mind wearing headphones that look like he just stepped out of the recording studio
he might consider AKG K 550. I'm very fond of the AKG K 702, but they are more expensive and require
an amp. I like the clarity of AKGs. And I understand the K 550s have better bass compared to their
big brother. That would be a good thing.
Smaller and more street friendly, he might consider the Beyerdynamic DT 1350. Very portable
If he would like to seem more stylish that everyone else wearing Beats, then I'm very fond of
Phiaton MS 400 appearance. I've read several encouraging reviews but have not heard them
myself. Some say it is a very smooth sound and comfortable for long periods.
If IEMs may be considered, then Etymotic ER-4S offer (possibly) unrivaled isolation and very clear sound.
Some find that these do not have enough bass... but I really like them. For a fuller sound
look at the Shure SE425. I've listened to these and liked them -- and can understand why almost
everyone would like them, but there was something I very much liked about the sound delivery
with the etymotic brand, so I went in that direction.
If he wanted very portable, over the head style of headphones, and wanted to spend just a little
bit more, then the Sennheiser HD25 Amperior would be an excellent choice. Lightweight, good style,
and excellent sound. Super portable.