In-ear silicone Extra Bass headphones MDR-XB20Ex. Probably the most expensive earphones I have bought and will ever buy, but I was sick of earphones breaking on me regularly so I bought an expensive pair, hoping they will last, and so far they have!
The silicone in-ear buds are much more comfortable than your average pair, and the bass sounds that they make is amazing (the XB in the name stands for "eXrta Bass"). The buds form a tight seal in your ear to stop music escaping and also stops a small amount of noise from getting in, although the are not completely sound-proof.
The earphones are stylish and are worth the money if you like the rich, low frequeny bass music when listening and hate buying a new pair of earphones every other week. It pays to invest in a good pair! Do not be drawn in by cheap, but weak, earphones, because you will spend A LOT more in the long run on them! Save yourself the hassle and buy a good, durable pair like these. Sony provide may different types of earphones and they are on display on their website!