Modern digital recordings are recorded, mixed and even mastered on computers. Pretty much off the shelf everyday computers. They tend to have powerful processors, tons of memory, vast storage, dedicated hardware I/O and can be supplemented with DSP boards. This doesn't mean you shouldn't try to optimize your playback, but it should serve as a point of reference.
Audio PC
How important is it to make sure an audio PC is built specifically for that purpose. Is cross talk between PC parts common in terms of creating noise that will be audible through monitors or headphones.
What steps would you guys reccomend to figure out if noise is being generated by components rather than a power outlet?
Is it very expensive to hire an electrician to install audio friendly outlets in your home/studio?