Based on your needs, you don’t really have to get an i7 CPU, that is more costly and there is not really a big advantage compared to an i5 CPU.
My suggestions are the following:
Motherboard Gigabyte GA-P55A-UD4 or, if you need a double LAN card onboard, GA-P55A-UD4P. Except for the dual LAN card, these two mainboards are identical.
CPU Core i5 750 (currently the best compromise between price and performance)
Hard disk This one to install operative system, and this or this for data storage. I suggest to keep separate disks for operative system-programs and for data. Creating separate partitions on the same disk for operative system and for data reduces performance.
CPU Fan Arctic Cooling Freezer 7 Pro Rev.2 This cooler is highly efficient and very silent. And it’s not huge like overclocker coolers, so you don’t need a larger case
Graphics MSI N210-MD512H. This card has a passive cooling, so no noise
OS Microsoft Windows 7 Professional (NL OEM 64bit). If you need to use some software that run only in XP, you need the Professional version. If not, then the Home Premium is ok
About these components, I think that your choices are good, but maybe someone can give you better suggestions
Memory Low Voltage OCZ3P1333LV4GK (2x = 8GB)
Case Antec Performance One P183 Black
Power Cooler Master Silent Pro M600
DVD drive Lite-On iHAS324
TV Card Hauppauge WinTV HVR-1300
Card reader Scythe Kama Reader 2