[neilc]

Well, in practice the latency that normaly matters is between "start doing activity" and "finish doing activity", and the time actualy working (that depends on bandwidth) is normaly orders of magnitude bigger than the time waiting for data (that depends on latency).

I don't think that's true; moreover, it is likely to become even less true in the future. Once the data needed for a computation has arrived at the CPU, for most applications the required computation is pretty cheap -- the time spent waiting for the data often dominates the time spent computing with the data. Much of modern CPU design has been devoted to trying to hide the high latency of memory accesses.