Here are my two recommendations:
- EarPeace Earplugs ($12.95)
- I bought these from Fab.com. They come in a really cute metal container that you can attach to your keychain or bag strap. They work fine and are great since they are reusable. After each use, just wash with warm soapy water and let air dry.
- A friend recently recommended these to me. I obviously got mine in Electro Pink, but they are also available in Gunmetal Black and Rouge Red. They come with several different sizes of earbuds to give you a comfortable fit and a detachable lanyard that allows you to hang them around your neck when not in use.
My vote is the for the V-MODA earplugs. The extra money is worth the convenience, comfort, and overall listening experience.