yes, there are different FSB for things like memory, CPU, ect. if all yo do is basic internet surfing and use MS word you will not see much difference. it is similair to the difference between ata100 and ata133 on hard disk as long as the program use up those resources moderately.
example is heavy flah animation, 3d modeling/ rendering, CPU/ memory dependant games like red alert 2: yuri's revenge. if you run cpu & memory instensive games and apps you will definately see a difference depending on which FSB you are talking about.