Anything new would be able to handle the light load you are expecting. For cost sake, I would suggest going with an AMD AM3 platform with an X2 or X3 processor. Look for a motherboard with an 800 series chipset, USB 3.0, SATA 6, and integrated video of HD 4200 or higher for 1080 resolution and Blu-ray playback. The power supply should have an "80 PLUS" efficiency rating (antec and corsair are good brands). Spinpoint F3 500GB or 1TB hard drives are often recommended.
Thanks for the answer.
I set on an Intel DH55TC , Intel core i3 530 2.93 GHz, Corsair 650w.