Just be sure you don't confuse bokeh with depth-of-field (DOF), they are not the same thing.
DOF is qualtifiable, bokeh is not.
Bokeh is entirely subjective and is a function of the mechanical attributes, glass properties, and construction of a lens, mainly the number and shape of the lens aperture blades.
A larger number of aperture blades that have nicely rounded edges usually produce a more pleasing bokeh effect.
A great comparison is to look at the jarring, jittery, odd looking bokeh produced by Canon's inexpensive, 5 bladed aperture, 50 mm prime lens and the super smooth, cream cheese, bokeh produced by Nikon's, 9 bladed, AF 85mm f/1.4D. The Nikon lens is nicknamed "The Cream Machine" because of it's remarkably smooth and homogenous.
Two kinds of bokeh are generally recognized as being desireable and pleasing:
- Cream Cheese Bokeh
- Hollywood Bokeh
Bokeh - Wikipedia, the free encyclopedia