Instead of using usb in mass storage mode like on the older phones, most/all htc phones (and all Nexus devices) from 2012 (android 4.1 and up) and onwards uses MTP mode for usb connections.
This is actually the easiest way to get music to your One X/X+/One/One Mini/One Max, since they all uses MTP which is a part of the media player framework.
This works on ALL Android devices that uses MTP for usb connection.
EDIT: this of course works on the new One M8 as well.
What is MTP then? it’s simply what’s been used in One S, One X and One X+ that’s running 4.1.1 (jelly bean). Stands for Media Transfer Protocol and is developed by Microsoft, and as you would guess it works very well on more recent versions of Windows.
But, you need an additional download on Windows XP to get it to work. Forget it on xp. And on mac? Sure, you can get it to work if you download the file needed for it.
Edit: MTP is also used in the new HTC One.