Given the three things you are trying to accomplish, all of which center around using it with your computer for backing tracks and recording, I would suggest looking at the line6 pod studio GX rather than the pocket pod.
Link: http://line6.com/podstudiogx/
It serves as a USB recording interface, and it has tons of amp models and effects (you manage them on the screen via software rather than with knobs on the device). I have the previous version, the Toneport GX and love it.