Berghaus Vapour Shell Goretex Trousers
Also known as the Vapour Shell Pant (I still find it strange adopting this Americanism and like to call trousers trousers, and not pants!).
It's pretty tricky writing in much depth about waterproof trousers. They are not a hugely technical piece of kit and really only serve one purpose - to keep out the rain and wind. The Vapour Shell's do that perfectly well whilst not creating sweaty microclimates inside at the same time. They weigh a respectably low 255g meaning that they definitely fit into the lightweight kit category in my store-room. They have three-quarter length zips which make putting on boots and crampons straightforward, as well as cooling off when necessary. They are comfortable around the waist thanks to the elasticated draw cord (something missing from so many previous pairs of over-trousers I've owner which resulted in them forever slipping down my hips!). And lastly they come inside a small stuff sack which means that despite the fact that they are relatiely lightweight they should last a year or two longer than they would otherwise do if you shoved them in and pull them out of your sack repeatedly.
Costing £140 they're on the steep side of affordable for a pair of waterproof trousers, but they strike a good balance between light weight and actual effectiveness (I have trousers that are half their weight, but only suitable for emergencies, mountain races etc, whereas these will work all day long. All in all they get the thumbs up from me.