depends on how much she want's to spend glenn. (pretty obvious i guess)
but heres the lowdown, if she want's to spend less than 1000, i'd just go w/ that energy saving thing that shows how a certain refrigerator at a cubic size rates vs other refrigerators for energy efficiency. you know what i mean right? you see them stuck on the refrigerators at all the stores.
if she is willing to spend more than $1000.00 than the thing to look for are the cabinet type refrigerators.
basically here's what happens, as we all know, heat rises. so it would seem most logical to place coldest component on the bottom and the hottest component on the top. that isn't what happens w/ most refrigerators. what you usually see is the compressor unit on the bottom, then heavy duty insulation, than the freezing unit on top. very inefficient.
the best refrigerators have the freezer unit on the bottom and the main refrigeration unit in the middle and the compressor on top.
they are hard to find and on the more expensive side.
hope this helps in some small way.