I believe the essence of KIFIS's question is with regard to thoughts and not the reaction to a thought, so I 'think' we can dispose of chemical reactions and electrical charge pulses as the basis for the 'speed of thought'.
I would hazard a guess at the need to focus more on 'conciousness' if we are to attempt to understand the process behind the creation of a thought and the time that process takes.
I for one believe that we create thoughts at a far greater speed that that of light (if we are to accept that the speed of light in a vacuum is constant at 299'792'458 m/s (metres per second)).
Contemporary physics states that no object should be able to travel faster than the speed of light, are thoughts objects?
[ 19 August 2001: Message edited by: Icarus ]