I am thinking of building a WHS 2011 box,

Will be used for:

Backups for 2 desktops 3 laptops (all windows 7 & 8)
Remote access to files and settings
VPN access into home LAN to RDP to PCs etc.
Media Server for music video photos
Recording TV for streaming around network

Motivation for this project:

Avoid my main pc having to be on all the time for most of these things ( TV recording and RDP etc) Also to centralise and manage backups for all devices as well as centralise all media.

Issues:

Recording TV using my Hauppauge HVR4000 under WHS, drivers software etc, i am guessing if i can get some drivers to work i can use media portal tv server ok. Any experience with using WHS for tv recording would be helpful.

Specs:

Mini -ITX H77 mobo (ASUS P8H77-I)
or maybe Micro - ATX

Mini ITX case (undecided - something small and quiet)

Low End Intel Core i3 CPU i3 3220?

8GB Ram (2x4gb)

2 x 2TB WD Caviar Green HDDs

WHS 2011 

400w ish Quiet PSU


Any issues with this, or is this overpowered? will need to stream and encode full HD to various devices.
Should i consider more HDDs and RAID?