I would tend to say otherwise
1 - concerning the PSU:
* there are FANLESS psu's out there. You must cash out the big bucks, but compared to enermax prices it's not too much. Just beware, they're ATX but they wont fit in many cases without some modding.
* if you want to keep your overpriced but beloved fanned PSU and still get rid of fans, because that whispering noise is bothering you (and youre not alone), watercool it. Use a straight block and mod the mosfets so you take them out with thick wires. Then put them on top of the waterblock which will replace stock heatsinks (you'll have to mod the WB somehow for this - add it some 'legs'). Just keep the water connections sticking out of the PSU and youre safe.
2 - a 15000rpm needs active cooling even under normal conditions. To eliminate noise you must:
* cut the noise by wrapping it in foam
* dampen the vibration between the HD and your case, with rubber bands for ex.
* this is possible only with some 5.1/4" adapter.
If you do this it will overheat and certainly fail. Since it *must* be totally wrapped up to be silenced, the only solution is still watercooling. Again a straight block (such as GPU blocks) will be enough.
Someone pointed me that D-Tek makes a fine HD waterblock as well.
Good luck
