The joomla default theme or makemyweb theme is 800x600 and 1024x768 dynamic screen resolution optimized.
Also the header image should have the same background fadeing as the joombers logo. And the top "orange line" should be red liek seen at the hover button. (Akzent color)
Also i asume this theme is symbolic for the joomla logo (4 ppl).
So maybe use green for mod area - orange for linkage - blue background and red style?
Beside that and all the other stuff looks really professional to me
Cheers
my 2 cents