AMD vs Intel Processors

I know this has the potential to turn into a flame war, but I'm not here to simply ask which is better.

I'm interested in building a new computer and considering trying different processors.  I'm pretty much an Intel person, but thinking about AMD.  My main question though is relating to the operating frequency (GHz)

Right now, I have an Intel Pentium 4 that is 3.0 GHz.  Looking at a comparable AMD chip is, for example, only like 1.8 - 2.+ GHz.  Now to me, this seems like a step back.  Isn't the higher frequency (GHz) more desireable?  How could an AMD possibly be faster?

AMD processors (and Pentium M's too) get more done per clock cycle. There are a large number of reasons for this (flushing pipelines of different lengths, number of execution units, signal propagation delay, memory latency, etc).

In fact, Intel has decided this is the way to go. The Core architecture they're currently finalizing is going AMD's (and everyone else's) direction.