In defence of waterproofs: whilst I have said that I prefer walking in a wicking layer plus a windproof, even in light rain, I still believe there is a case for waterproofs on the hills.
Don't get me wrong, I understand and agree with most of what Andy Kirkpatrick says, and when climbing the gouter arete in I did it wearing a t shirt and lightweight windproof and I still had steam billowing out of my open jacket, I even took my gloves off I was that hot. I would have had heatstroke if I was wearing a waterproof.
When walking up hills I prefer the same system... however, when its pouring down I will wear waterproofs, to stop myself sweating so much I slow my pace down, and take it easy, and I'm not always climbing up hills, sometimes I'm walking on top of them or even down them, which is a lot easier and less heat builds up, and any sweat that has built up whilst climbing will slowly evaporate and leave me dry inside (moisture will travel through them... eventually).
This is especially true in the winter months, or if its really windy (like today), when the outside temperature / conditions also play a part in regulating my body temperature.
So whilst I agree that the breathability of waterproofs is a marketing myth, some of them allow more moisture transfer than others, and they do a job, so that's why I still wear them... occasionally