I've always believed in minimal computing. Whether it's at home or at work, I surround myself with only the things I need to be able to complete the task at hand.
For example, at home, my desk consists of a MacBook Pro connected to a single Apple Cinema Display, with a wireless magic mouse and keyboard. There are no pictures, no post-it notes and no stationary, because for my work I simply don't need these items and they would only act as a distraction.
I continue this direction in the office, where I have a large desk, but am reduced to just a wireless keyboard, mouse and 24" display (the notebook itself is hidden away). This style generates a fair amount of surprise from people around me and those visiting my desk, where I get question like "do you do any work?". But I consider this experience optimised, perfect for my needs and clear from foreign stimulus.
Now this level of minimalism may not be perfect for everyone and that's important to remember. The dictionary definition of minimal is "only barely adequate", but that means it still needs to be usable. I work in IT, therefore as long as I have a computer connected to the Internet, I can get on with my job. The majority of my day is spent working on local applications, network devices, servers or virtual environments (most of which are accessed remotely). As a result, I am able to get away with an "extreme minimal" setup, but it is important that you find the right balance, as there is no point being minimal if you spend your entire day searching for a pen!
I also believe that minimal should not only apply to your physical desk, but also your computer desktop as well. Below is an image of my current desktop, as you can see it is clean and distraction free. I have a bold, simple background and I access all my files and applications using the quick launcher Alfred (but Spotlight works fine to), therefore I rarely need access to the Finder or Dock. I am able to quickly and efficiently jump between applications or projects with a few simple clicks of the keyboard (or a single gesture with Mac OS X Lion).
So, if your desk has 300 old coffee cups and a pile of physical files that you haven't opened in 10 years, or if your computer desktop is so busy that you can't remember what your background looks like, then I urge you to try a minimal experience. I promise that a minimal environment will heighten your focus, creating a "zen" like state, allowing you to concentrate for longer periods and therefore becoming more productive.