Bill got the Motorola Moto-X, and he wants to know if he can use his good Sennheiser headphones with it. Leo says it should work. The headphones he's using will have three black rings on the tip, and it should work when plugged into the headphone jack of the Moto X. If the mic doesn't work, then that means it can't support the inline mic of the headphones.
Leo uses the Etymotics HF3, which are very high end. But there's lower end models that work great too.
He may also want to look for an adapter plug. Lifehacker has an article on How to Turn Your Favorite Headphones into a Headset, which includes a Belkin $10 mic adapter.
PadreSJ says the Headset Buddy does it all. It's $15.95 on Amazon.