Trays?
 

Not to complain but what is the purpose of the trays you are giving the option of? I spent some time organizing a decent interface with them only to find I cannot place skills in them. Are they just for looks or is there an option I have to select for them to become usable, or it is this just completely unintended. OIther than that as far aesthetics go this is the best interface Ive used yet.

They're meant to be used with Flexbar, which doesn't have any graphics to speak of on its own. That way you can move your flexbar buttons around on top of these graphical bits, and have a nice looking and functional UI.

You can get flexbar here - there is a "flexbar for dummies.txt" file included with DiivSkins that should contain some tips for using flexbar, because it is very flexable, but that also makes it a bit intimidating when you start out using it.
Hope this helps!