The improvement (or degradation) in sound depends on how dirty your AC is. In many urban areas (most probably), the AC is likely to be sorely polluted by the high density of appliances, machinery, RF interference, etc, that tend to degrade the sound of your audio system pretty significantly. In these cases, even an inexpensive (yet decent) power conditioner will have a noticeable impact. In areas where the AC is relatively clean, adding in filtering where its not needed simply puts one more sink between your equipment and the power it needs. You'll need to make the call relative to your area.
I put a Monster HTS-2500 in line with my system and the improvement was pretty dramatic. You might want to see if you can borrow one of these units (or the smaller HTS-2000) from a dealer (it seems as though everyone carries Monster these days) and see if you notice any improvements. If you do, then you might want to consider auditioning PC units and find the one that suits you best. If you don't notice any immediate changes, then its unlikely that any of the lower priced power conditioners will offer much value (other than surge protection, but that's another thread).
-- Ken
I put a Monster HTS-2500 in line with my system and the improvement was pretty dramatic. You might want to see if you can borrow one of these units (or the smaller HTS-2000) from a dealer (it seems as though everyone carries Monster these days) and see if you notice any improvements. If you do, then you might want to consider auditioning PC units and find the one that suits you best. If you don't notice any immediate changes, then its unlikely that any of the lower priced power conditioners will offer much value (other than surge protection, but that's another thread).
-- Ken