I know that there are many Nikon fan boys out there just loving the sound of the burst modes their cameras make when you keep the shutter button down. The Nikon D4 has a burst rate of 10fps(frames per second) which is equal to a AK-47 assault rifle. In this video will see the comparison of the difference in burst modes for the Nikon D700, D3X, D300S, D7000, D800 and D4
Of course the burst mode is subjective to the photographer, it does sound pretty darn great to be shooting like a machine gun. However not everyone can afford it and nor do they actually need it. Personally I was more than happy when I upgraded from my Nikon D80 which had a 3fps to the D7000 which featured doubled of that, 6fps. Frankly I do have to admit that I rarely use the highest setting on this camera, as with subjects I shoot, the need to shoot 6fps rarely arises.
If you shoot motor sports, athletics and wild life then perhaps a DLSR with higher frames per second would be necessity. For the rest of us having high fps is just for boasting purposes.