I've become increasingly interested in Carl Zeiss lenses, but still don't know if I'll actually spring for one. The 35mm f/2 Distagon seems to fit the bill for a high quality fast prime for under $1,000 (unlike the Canon 35mm f/1.4). No autofocus, though :)
Anyways, Zeiss has a newsletter and currently has a very comprehensive PDF that goes over many of the challenges of lens design and how it affects the characteristics of how a lens 'draws', among other things, the out of focus areas and results in good or bad bokeh. Of note are a few key points and reminders about bokeh - there are many misconceptions out there: the bottom line is that there is more to it that just the number of blades (though that helps too!).