Recently through a mistake I got two pairs of the same earbuds, so I've been using earbuds both at my computer in my dorm and for my iPod everywhere else. I used to prefer headphones, but I've found that only the large and expensive ones can both give me the sound blockage I want AND stand up to the wear and tear I put them through. That is a problem because I don't exactly have a few hundred dollars to bust on a pair of headphones and I don't want a separate carrying case just for my headphones.
The earbuds act like ear plugs and can bring the loudest of background noise to a tolerable level. The type I get are the ones that run around $20 at WalMart and come in every color of the rainbow. They last me close to a year too, which is very impressive since most others usually only last three or six months.
Also, I'm a stickler for quality, and those earbuds give me excellent quality. I feel like I can also hear more nuances in the music with them, since they block out so much sound and deliver the sound so precisely to my ear. And they leak next to no sound. Regular headphones now make the sound feel more far away to me.
And lastly, for the record, I can't stand the type of ear buds that iPods come with. The ones I'm talking about are the ones that actually go into your ear, and are shaped like ear plugs. The iPod headphones are uncomfortable, never stay in my ears, and let in a lot of noise.