I like Duluth Trading Company pants... both their regular 'firehose' pants which seem very tough and well made, as well as their quick dry nylon pants -- which are also made tough.
I just got a pair of Aerostich AD1 pants -- expensive, especially considering our low dollar, but they are waterproof as they claim (tested them yesterday) and as long as you keep moving they are also cool enough as the goretex breathes. They are a bit much stopped at traffic lights in the heat though. They seem to have the knee pads well designed that they don't move around like other pants I've tried and they reside over my knees, which is a bonus for taking a chance on the sizing and not being sized by Aerostich.