Until we can create software to use all the cores ghz IS important. The N900 loads/renders web-pages way too slowly. And when external HDMI screens can be connected that speed will be even more important.

Furthermore, don't make the mistake of assuming the current OMAP's battery efficiency will hold for the next generation of chips. The upcoming chips run at high speed, are polycoreus AND have a longer battery life.

The idea that chip speed doesn't matter because "software should be optimized" begs the question; people are talking about the SAME level of optimization on a faster chip. Thus, faster experience and better UX. Are you thinking that developers will "unoptimize" the code so that it will still perform poorly on faster hardware? We're unlikely to do that.