You know that you can connect tv and joystick to PC don't you?
65" is pretty tiny. Try playing on a nice hd projector on 5m screen
Your dilemma is very simple. Do you want to play mmorpgs? Then upgrade PC. Do you want to be able to play the game and chat in skype/icq/social networks or browse internet or watch movies in the same time? Then upgrade PC.
As of d3 I can't imagine myself playing it without battle.net, so consoles are not an option. Item trading, ladders, ladder-only bosses and items, cheat-free environment - all this makes PC version one and the only option.