Thanks for the responses.
After reading the forums it seems that the Gigabyte gets hot (+100C) (but it would have been cooled by the 250) and that the HIS 4850 ICEQ also has noise issues, never noticed with the old ATI9800pro from HIS, even after 5-6 years (last 3 as backup pc).
The 250 isn't bad either, little better performance, better driver but no decent HDMI with Audio (needs a cable).
But won't mixing the 2 (ATI on board for HDMI with sound for the tv and Nvidia 250 for gaming) give problems?
Regarding the noise the 250mm fan, I was in KME Koln last week, where they have such a phoenix neo as demo pc housing. It didn't make much noise, it was hardly audible.
For the housing, one with a front door can not be used because of the sound card front bay, which is recycled from the old pc, I have to use headphones regularly so the volume control on the front panel is very handy, so is the remote control.
Also a front eSata would be very useful. A full set of Noiseblocker Evolution EQ Platinum is also hiding somewhere.
The reason for the mobo is the number of PCIe (require 2 PCIe 4x and 2 PCI), so this was the cheapest from Asus that is available in store, the CPU for being save for another 3-5 years.
My idea was to reduce the number of fans and depend on the 250 to blow in cool air and the PSU and a 120mm exhaust fan to blow out the hot air.
Placing the HDD in a zalman hdd cooler to reduce noise and keep it cool.
Even try to have the CPU only cooled using the CoolerMaster GeminII or Thermalright Ultra-120 without a fan on it (again using the 250).
But now thinking of placing a PWM fan on the Ultra-120.
In a way reduce the number of air moving/sound producing parts thus reducing sound.
But it seems that idea isn't good