CPU+MB: Intel Core i3-4130 + ASRock H81M-HDS @ $218
This strong dual core CPU with hyperthreading will already be overkill for regular home usage even in the several years to come.
Intel HD Graphics 4400 is on par in gaming performance with AMD's Radeon HD 8470D on their A6 APUs, while utilising much lesser power for H.264 encoded videos (mostly on your HD clips).
RAM: ADATA Premier DDR3-1600 CL11 4GB @ $43*
Since DDR3 prices are on the spike, and 4GB is already aplenty for such purpose, he should make do with it and then determine if he really ever needs another stick instead of filling it up to a full 8GB, potentially wasting underutilised capacity and money..
SSD: Plextor M5S 128GB @ $127
HDD: Hitachi Deskstar 7K1000.D 1TB @ $80*
ODD: Samsung 24X CD/DVD Writer [OEM] @ $21
PSU: FSP Raider 450W [80 Plus Sliver] @ $75*
CASE: Sharkoon MS140 @ $52
DSP: Dell UltraSharp U2312HM 23" LED [eIPS Panel] @ $248
Total: $864
Optional:
CPU+MB: Intel Core i5-4440 + ASRock H81M-HDS @ $302
Buy and Build from Tradepac, #05-19.