With all the time I have spent with a countless number of designers on the web there is one thing that can help to separate the great ones from the good ones. Great designers know what they are going with when they begin to design a site. The know the style that will fit their vision and they roll with it. Other designers like to look around for inspiration while figuring out how they wish to go about the design of the site.
Now I like to look at beautiful sites as much as the next guy, but in designing BullieBoard I caught myself using certain design elements of a site that I just got done looking at. Because of this the design was forming the way I thought it should in my head, but simply how I remembered another site using an element of design. It finally got to the point where I stripped all styles and started from scratch. As you can see not much more was added, but it got me to where I wanted to go.
So go around and continue building up your design repository by studying different designs, but when it is time to start a design yourself, cutoff all methods of looking for inspiration. You are a designer and your design should come from your instincts, not your memory of how another site did it.