Something I would like to have in my GUI utopia is to have the option to make a desktop folder. Not what your thinking. It's a folder where you can move the icons around so you can have layers on top of layers of miniature desktops so you can move things around how you like. Oh, and it doesn't have that stupid grid system like default windows does. don't like it: don't use it. But it would make navigating my projects so much faster while also helping me be more organized. maybe have it so you can have folder backgrounds too.
and speaking of desktops: that multi-dimensional desktop thing at 1:13:09 would also be on my list. it would be just cool and nice because I use three different desktops at all times: my main, school, and stuff I want to deal with later. maybe have it so the shape depends on of many desktops you have. so having four would get you a pyramid, six gets you a cube and so on.
having icon themes, this only apples to default system icons; but it would be nice to have a default theme, maybe a prehistoric or sci-fi theme that you can easily change to help make the computer look nicer. It's like if the icons had different font.
maybe a dues ex style (different colors possible) windows for file explorer (except for those desktop folders I was talking about) would be cool to have as an option.
maybe also have a transparency effect like in windows 7, because that was just cool looking for me.
I'll add on to my list if I come up with anything else.