There isn't any odd sounds that I can tell. Though I hadn't thought of the A/C causing anything - I couldn't say whether it was doing it only while it was on or not.

The alternator is less than a year old (replaced under warranty), battery is less than a year old (Red Top).

No problems with start up, so I'm assuming it wouldn't have anything to do with the alternator or battery. No warning lights have come on at all (except when the idle is dipping to near zero).
_________________________
"Nature has constituted utility to man the standard and test of virtue. Men living in different countries, under different circumstances, different habits and regimens, may have different utilities; the same act, therefore, may be useful and consequently virtuous in one country which is injurious and vicious in another differently circumstanced" - Thomas Jefferson, moral relativist