Sandy Bridge components needed

Hi All,
I've bought in the last few days the following components (after many forum thread read) -

CPU: Intel Core i5-2400S 2.50GHz (65W, 6MB Cache)
CPU Cooler: Scythe Big Shuriken Low Profile CPU Cooler SCBSK-1000
SSD: OCZ VERTEX 30GB
HDD: SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB Cache SATA x 2
Case: Silverstone Grandia GD05 (3x120mm fans)
Memory: G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 DDR3 1333 CL8 (F3-10666CL8D-4GBRM)

My system purpose is mainly HTPC (should be as silent as it can be) with light-medium gaming (but using a passive GPU) and once in a while photo/video editing/rendering

I need to have your opinions regarding the following components in order to complete my setup.

MOB: ?? (should support undervolting the 3 x 120mm fans of the case, or if you have any other idea ...)
GPU: ?? (should be passive)
PSU: Might be Enermax Modu87/Pro87+ 500W or Seasonic X-650 or anything else which is very quiet, efficient and modular
DVD: ?? (but it won't be a BR-Drive)
Mouse/Keyboard: might be Logitech DiNovo Edge but if you have any recommendations it would be nice to compare with.