@Pangloss,
A desktop computer always have wires running everywhere and it is under the desk not on top of it for the most part so having a low voltage power cable running to it back seem hardly a great aesthetic problem.
Less see I now have four USB cables, an AC power cable, a keyboard and mouse cables, speaker cables. All of them behind and or under the desk.
The USB cables hook up to my fax/printer/scanner, two external hard drives and one free to hook up to my camera or my mp3 player.
Phone connections to my fax/printer and on and on we go.
So instead of an AC cable I would had a low voltage cable running to the back of the computer and I can not see the big deal.