Yes, it can. I was able to switch into the dark theme without any hacks.
The Express edition cannot use themes, although I was able to find a hack to make it work.
Try the dark theme, if you haven't already. It's much easier on the eyes.I'm using the Express edition, which means that I have a fraction of the available features and the ones that I do have are gimped.
With that said, the interface SUCKS! I have an 8-core processor, 16 GB of RAM and an AMD 7870. While this is a moderate to high end system, I have seen very nice GUIs rendered quickly on much lower end systems. Why, in the name of God, did they decide that we all want to take a giant leap back and do a flat, monochrome interface?! I have a very hard time just trying to find GUI elements on screen. Windows 3.1 GUI was better than this!
Go to Tools->Options, then in the drop-down on the left hand side select Environment->General. Then, under the "visual experience" pane, there should be a drop-down labelled "color theme" which lets you switch between "Dark" and "Light."