I've got an 80GB barracuda and a 120GB WD my self, both IDE, and I can't hear a thing. Also the heat don't seem to be a problem, my comp runs nice and cool. These drives has been with me for about 3 or 4 years now and they still run perfectly fine. (maybe I should mention that I do have a 80mm fan blowing directly on em')
Since your comp. doesn't exactly strike me as an enthusiast PC I believe you would be satisfied with any HDD of a decent quality, and I believe the leading branch's (Seagate, WD, Hitachi, Samsung, IBM) would all live up to your satisfaction, the only thing I would be looking for within these 5 branch's would be speed, of course I would want the fastest drive for the money.
I'm not sure I can say much more to lead you in the right direction, I'm not exactly an expert on HDD's, I was just waiting for an answer to my own question and figured I might as well give a fellow poster my 2 cents on his problem.