I have also a P4 1,8 GHz at work
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The Netburst architecture (foundation for Prescott processors) wasn't a good idea; so deeply pipelined processors to allow higher clock rates at any cost and the move to 90nm didn't prove a wise move. Intel had to scrap them when it was evident that Prescott won't scale as well as expected. Things were pretty bad beyond 3,2 GHz with thermal envelopes over 120W.
It has taken some time for Intel to find a better approach, but it is slowly starting to build much efficient processors. Recently I tested one of the new Intel 820 (doble core, 2.8 GHz 2x1MB L2 cache 90nm) and I found that it ran cooler than a Pentium 630 or 530. In fact I was surprised to find it a lot more efficient than expected, based on my experience with Prescotts. And the new Intel Core Duo processors are promising.
However AMD has the edge on multi core processing. Their dual core processors are really dual core: two processing units communicated with an Xbar switch. Intel approach has two processors that only share the same dye, but are not connected internally. Anyway things are starting to be very interesting in the CPU market, we're no longer stuck to the race in MHz which ultimately proven to be a dead end.