Thanks guys. the Seasonic X-650 looks great too, I'll see for how much I can sell my hx620 to get the seasonic instead, If it wont sell for a good price I'll go with the fan swap recommendend, thanks CA_Steve. My CPU is the i7 2600K on a Asus p8z68 deluxe. well you're probably right with the gpu usage by video editing; as long as I'm still not using Blender for 3d, I guess my passive-cooled videocard should be sufficient. The workstation is placed in a controllroom outsie of the recording room so the noise is not that criticall, but still a silent workstation is something i'm after.
Why would you add more fans? It doesn't look like you need them...
well I was thinking to add one intake and one exhaust fan, the noctua one probably with a ultra-low noise adapter again.. because i think two fans with lownoise adapters are still better then one without an adapter (noise-level-wise), I might be wrong though.. and I still haven't tested the temperatures in the machine under long, havy load..
What are your ideas on accoustic insulation inside the case? and soft mounting of hdd's? Is that as easy as puting some rubber washers/rings between the hdd and the mounting cage? I'm also starting to think about using a Silentmaxx HD Silencer Rev. 2.0 for my 7200rpm hdd as the seek noise of my WD caviar black is soo loud!