Comment 10 for bug 346878

Basically the data we have to go on from ALSA is "USB Audio" and "USB-Audio - Logitech USB Headset", both of which don't help us because they are the same for each device.

For the next release, I will change it so that in the case that there are two devices with the same name, we will also append the ALSA device numbers. Your list will then look like this:
Default
ALC268 Analog (hw:0,0)
ALC268 Analog (hw:0,4)
USB Audio (hw:1,0)
USB Audio (hw:2,0)

Presumably in the case of USB, the higher numbered device is the one that was most recently plugged in.
Unless anyone has another suggestion I don't think we can do anymore than this.