My favorite type of photography is available light portraits so I can't help but pay attention to bokeh.
Originally Posted by colonel
I am qualified to answer this question because I only use Rolleiflex cameras for reasons that are independent to the bokeh properties.
This is only from what I've read but...
Most MF lenses (Pentax, Mamiya TLR/SLR, Hasselblad, Bronica, etc.) seem to be suitable/good but the Mamiya RF lenses seem to be knocked down the most and also Fuji RF lenses. From what I've read, the Mamiya Rangefinder lenses were designed to be very high contrast and so the bokeh is very busy. Similar with the Fuji RF's (The GF670 is an exception though). Most people believe that the bokeh on these RF lenses are either bad or "suiteable" but nobody really raves about them.
The most hyped MF bokeh for a normal lens typically belongs to:
Rolleiflex 80mm f2.8,
Nikkor 80mm f2.8 (Plaubel Makina), and
Hasselblad 110mm f2.0 (really expensive though and you need a 200/2000 series Hasselblad).
But these are all very different cameras.
I've had 5 Rollei's from MX-EVS (Tessar) to 2.8E (Planar), and they've all been excellent:
Even the Tessar:
Untitled by Michael_Sergio_Barnes, on Flickr