Korg VC-10
Korg VC-10 is not a very good vocoder - most agree on that. Speech or
vocals sent through it becomes unintelligible and murky, and percussive
material looses much of its attack and pucnch. 
However, the
VC-10 is an excellent instrument and also an example of elegant and
suitable exterior design!
On the outside, the VC-10 is much like the mono synths in Korg's MS series, but with fewer knobs and a very suave-looking goose-neck microphone attached to the top. A two and a half octave keyboard controls the internal sound source, which is a simple, fully polyphonic organ with triple vibrato circuits and an absurdly fat ensemble effect that can be activated if so desired (sounds like a chorus on acid - we have used this ensemble effect by itself some times, e.g. for the Clavinet). The keyboard can be transposed one octave up and a non-springloaded pitch bend wheel allows polyphonic pitch sweeps. The pitch can also be modulated by a CV-pedal or follow the amplitude of the modulation signal (a strange auto bend effect, which we yet have to explore and use).
The actual vocoder process is truly a "black box", though -
there are no settings whatsoever for this, other than level adjustments
for the carrier and modulator signals. 
These can either
be the built-in "organ" and the gooseneck microphone, or external
sources, in any combination. A beautiful old-fashioned VU-meter shows the
signal level for either of these.
What then makes the VC-10 such a good instrument, you ask? Well, the unpredictable vocoder process, the infernal wobbling of the triple vibrato and ensemble and the high uncertainty factor of the pitch bend wheel makes the VC-10 a very much "alive" (and difficult) instrument. We have used it several times for sweeping pads or sax riffs, just for this organic quality. That you more or less automatically get the classic "Disney choir" sound just by playing a chord and saying aaah - that's no bad thing either. You can hear the characteric sound of the VC-10 in e.g. Stampede or East St Louis Toodle-oo.
One more thing: our VC-10 is equipped with Korg's original microphone, but the volume knob is replaced with a slightly larger knob in old-fashioned brown bakelite, with a small, embossed golden arrow (done by its previous owner). There's nothing like standing in your tuxedo, singing Disney choirs in a gooseneck microphone while adjusting a big bakelite knob!