As I explained last week, bokeh refers to the character of the blur itself, which generally means the shape and crispness of the blurry elements. The blur in your photos is affected by the lens--primarily, the design of the optics and the aperture.
The result is that you can actually see the shape of the lens aperture in your blurry backgrounds (especially in light sources and reflections). Of course, lenses tend to be round, so these blurry spots are generally round as well--but they can be geometric, depending upon the number and arrangement of blades in the lens aperture.
Of course, you've probably figured out by now that you can't do much about the overall quality of the bokeh created by your lens. Your lens is constructed a certain way. It has a given number of blades, for example, and the blades have an unalterable shape that contributes to the bokeh (as well as the optics of the glass elements). You can't open up the lens and change the blades to modify the look of the blur.