Looking for a good ground in/ner my AV cabinet for APC ProtectNet surge protector

You can connect the ground wire to equipment that has a grounded case (3-prong plug) or to the building equipment grounding conductor. Assuming you have properly grounded electrical receptacles, the easiest way to do the latter might be to use the screw that holds the plate to the receptacle. It needs to be bare metal where it touches the spade lug, of course.