.. which is the be.. naah most appropiate will totally depend on which signal type you are to handle.

For instance for a 74HC input, if you, speedwise, can handle a parallel capacitance and a series resistor, that will, most likey, suffice, since the HC can clamp 20mA either way, which will not help you if the risetime exceed the clamping diodes reaction time (thus the series resistor). For instance, for some slow signals I have 1nF from pin to ground and 10k in series with the input. Now, if you have any speed issues or 'loading' inputs, the transzorbs and ferrites etc come in.

Erik