It's hard to tell how much quieter it makes your hard drive, but I barely hear my Raptor running in it (dunno if it's the Raptor is just a quiet drive or what) - and the Cooldrive 3 itself is practically inaudible. If you're worried about case noise, this cooler certainly won't contribute to it. I've got a Zalman running at low RPM and Rheobus keeping my case fans at low speed to cut down on noise, and I'm not able to hear the CD3 at all.
As for the new system, the MSI Meo-LSR crapped out on me Thursday but I eventually got it back up and running. I'm RMA'ing it and have an Abit IC7 on the way to replace it. But the MSI's keeping me running 'til then.
-J