The problem seems to be that any proposed improvements or changes to the graphical user interface are either too evolutionary to be significant, or too radical to be practical. The key seems to be to strike a balance between offering genuine improvement, but at the same time, be recognisable enough so that 'normal' users can identify with it effortlessly. I rarely, if ever, encounter such an improvement - until a few days ago. Cue Grape.
Everyone uses their desktop differently. Personally, I tend to use the graphical desktop as I use my normal desktop: as a temporary location for the stuff I'm currently working on. In addition, when it's Monday, and I need to publish a certain article by Thursday, I dump the corresponding file on my desktop as a sort of reminder. As soon as I'm done with a file, it's moved away from the desktop - either trashed, or filed away in my OCD-inspired directory structure. Yann Le Coroller's Grape concept seems to be tailor-made for my kind of usage pattern.
The idea is that any file you drop onto the desktop automatically turns into a preview of that file - images, text documents, videos, and so on. You can then manipulate these previews by resizing them, moving them around, or flipping them over to edit their metadata and properties - this includes folders. You can 'group' these files by dragging a box around it (a 'pile'); you can also name the pile, and colourise its 'box'.
The key is zooming. When you zoom out of a pile, the previews in the pile will cuddle up together, and your desktop area will expand to reveal more space for more piles. When you zoom back in, the pile unravels so you can see the individual files. You can of course make one preview larger than the other if you so desire.
In Grape, you organise your desktop graphically and spatially: the more important a pile or individual file is, the larger and more prominent you make it. And can't find a file? You can click the 'find' tool, and graphically find the file you need (using 'highlights', as Spotlight does in Mac OS X' System Preferences application).
What makes Grape so appealing is that contrary to many other proposed improvements, it's actually not a replacement; something like Grape can easily be an optional component draped over a traditional desktop, something that you may use - or not, at your own discretion. Addition, not substitution. However, seeing the stunningly good looking and elegant conceptual implementation by Yann Le Coroller, I can't imagine anyone not wanting to try this out.
I can confidently say that this is one of the most impressive and elegant GUI concepts I have ever seen. I hope someone steps up and turns this into a reality - on Mac OS X, all the components to do so appear to be there (Spotlight, Quick Look, Core Animation, etc.).