Quite so, my Studio 1555 is a 65W unit and my LCD monitor is now aging. Even with my 60W Acer AL1916W drawing power I use less than the Mac Mini would. And when I don't need it I turn off the LCD.
Doing a little math based off my electrical bill, my laptop and LCD (together) cost me $112.57/yr USD. At roughly $240/yr for the Mac Mini alone ... I'd say that my Dell laptop wins out.