HDD just contain the data not the audio. It's not audio until it hits the sound card, with that said, there's mechanical and electrical noise you can consider. i.e. wall-wart vs bus-powered, to me less is more, so I prefer the bus-powered but for capacity reasons if you select a larger HDD, the wall-wart might need attention. For mechanical noise, the slower the rotational speed the less mechanical noise it can create, if it's just audio you aren't after speed here, so select a green drive or a 5400 rpm drive. I like the g-techs, but they are typically built for speed, but since most don't have a fan or have a very silent fan, it's a solid choice still, but you might hear it now and then.
