I currently have a HP Proliant Microserver that has an AMD Athlon II Neo N36L Dual Core 1.3Ghz processor. I use this for remote downloading and to stream media around the house. It does the job pretty well.

Now, I want to build a mining rig. As the 5850 are the best price/performance cards then I would use these cards to mine with.

That essentially just leaves the CPU. I want to keep costs as low as possible so I am after a CPU which would be the same or better than the one in my server for streaming media.

I've already got HDD's, a PSU, RAM (see below) and a case
It would also need a wireless card too because its going in the garage

All I really need recommending are the Motherboard and CPU. Would anyone be able to recommend me some?