Single-user mode, data recovery, mount usb
You may also want to consider the Recovery partition if it's accessible.  Use CMD+R at boot to launch into Recovery mode.  This would let you mount a USB stick or even a network connection to transfer files.  

If you do have another computer available, you could boot this Mac into Target Disk Mode by holding the "T" key down at boot when you see the Apple logo.  This would allow you to then use the FireWire or Thunderbolt connection to plug your computer into another as a disk drive.