I've spun some of the cubes around a bit to highlight the reflections of the other cubes, and tweaked the positions of some of the colours.
At the moment I'm not entirely sure what more I can do for it, aside from adding some glow to the pillars themselves. Not something I really want to do just yet, but I guess it's an option.
Created entirely within Blender. Rendered using Cycles, post-processing with the Compositor.
Check out my gallery on DeviantArt for the 3840x2160 version for wallpaper!