In reply to Jon Hemlock:
Waterproof trousers have one serious problem. We tend to move our legs when going up hills.
That's it really. That's the problem. Its not the membrane or the taping or anything to do with the material. You can invent whatever material you like for a jacket but trousers are doomed.
Partial Solutions:
1. Size.
I know you want to look cool and sleek but it will end up as cold and wet and sleek. Those well-fitting ones will last 5 minutes tops because the gusset area will be stretched and ruined in the first few steps. Buy a bigger size.
2. Pants.
Same problem as occurs with jackets. If you wear sh1te underneath it you will get sh1te performance. Get rid of the cotton boxers and buy Helly or Damart pants.
3. Knees.
I have a pair of Bundeswehr Goretex breeches. My gaiters cover my lower legs so I dont need trousers to cover them. The breeches fix with velcro and a popper around the top of the gaiter and are fairly baggy at the knee. This means no repeated stretch of the Goretex round the knee and therefore no breach of the membrane. No other solution, no matter what the expense or technology, has worked as well as these breeches.