The Sol Republic Tracks headphones aren't like other headphones (although they look suspiciously like the Beats by Dre cans), as you have to actually build them. (Although don't panic - it's not that difficult. Just slot the earpieces on the headphones and you're good to go.) As a result, they come in a variety of different colours, and can be customised.
Great sound quality comes as standard, but the real travel bonus of these guys is the sturdiness of the Tracks. The headband is "virtually indestructible" according to Sol Republic, and the cable is thick and durable. You could bury them on the beach, drop them on the floor at Heathrow and chuck them across your hotel room and they'd survive. Result.
Oh – and Michael Phelps likes them. Need we say more?