Generally, most people try to find a tv with a "power resume" feature, meaning that if the tv is on, and the power goes out, when it comes back on, the TV "comes back on" too.
That way, you just hook the tv and the PC up to a smart power strip, with the PC as the master. Then when you turn the PC on, everything else on the strip automatically powers up.
Clean, simple, cheap, no rewiring.