I have a sharper image Ionic fan unit here at work and love it. Though its getting old and the only setting it has is high and sounds like an aircraft taking off (probably some belt or some mechanical widget is loose or something).

Working in cube land, you notice it working especially in the afternoon.

I would highly recommend it.
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"One should not increase, beyond what is necessary, the number of entities required to explain anything"
William of Ockham (1285-1349)