So, when idling, if I have the transmission in neutral, when I let off the clutch, I can feel a slight shaking and a the engine load changes just a bit... nothing major.

Is this a clutch adjustment of any type, or a failing throw out bearing or something along those lines?

The car supposedly had a fresh clutch in it before I got it, so I'm not sure why they would have had it apart and not changed the bearings and such... just seeing if I'm due for pulling the tranny soon :-/