> I would think the resistive losses in a capacitor is going to be 
> insignificant, the reactance losses are another story, remember 
> were dealing with A.C.

Um, um, um...  all losses are ultimately resistive aren't they??
Resistive losses in a cap with unsuitable dielectric can be very 
significant indeed. Gary Weaver posted something on glass vs rolled 
poly recently. I'll also quote Mark Barton who started out with
beer bottle type caps: "the change when we went from homemade caps to 
commercial was more than subtle with snapping white discharges....".
    IMHO, _all_ reactive power is lossless (returned to the supply 
if no resistance interposes). Radiation is also modelled as a 
resistive loss.


> Your also forgetting that inductors also have 
> hysteresis losses.  

Which also are resistive.