My computer is under warranty until August, but at this point, I have no idea what else can be fixed/replaced and none of the techs at the Apple store could even hear the hiss/whine (except for one tech in the backroom, apparently). D:

This doesn't appear to be a common issue -- at least, not for newer models (it was a problem for some of the older Macbook Pros). Even though I still don't think that Macs are superior to PCs, Apple's customer service is definitely better than any other company's! Out of curiosity, what's the brand of your current PC?