Yeah, very very annoying and stupid. And if you have a lousy laptop TN monitor, like I do, it's sometimes even more difficult to tell the colors apart. You have to pause and analyze which item is the selected one and which is just the random place the mouse pointer happens to be. With all the people Microsoft has for UI and whatnot I don't understand how they come up with such glaring gaffes.
I've found no registry way to disable this when I researched it a few months ago on Windows 8.0. Maybe sometimes changed in 8.1, but I doubt it. The only solution I found is to edit the Windows skin/theme to remove the hover highlight, and use an unsigned theme service (I think it was UxStyle?). I still need to do this after upgrading to Windows 8.1.
By the way, there are two skin elements that need editing if you want it 100% solved: the hover on unselected items, and the hover on selected (i.e., keyboard selection focus; Ctrl-Arrows).