w/o reading through the answers, 
this is a pretty stupid poll, because it depends on too many conditions 
How fast I drove would depend on:
a.  amount of traffic
b.  speed of other traffic
c.  condition/type of car I was driving
d.  how I felt at that time.   
e.  condition of the road (try the interstate near me... 65 will rattle your car apart)
Under ideal circumstances, I might do 90-95.