Lots of good recommendations. Historically, I have done well with Specialized, Gore, Aerotech Designs, Pearl izumi, and Bellweather.
As for durability, they all seem to wear out at about the same rate. I rotate among 2 or 3 pair, and inevitably, the material gets thin and translucent, at which point, it is time to retire them, or just relegate them to use on a trainer. Last year, two of my favorites, the Specialized and the Gore shorts wore out, and I wound up replacing them with the Aerotech and Pearl Shorts. It is hard to lock into one brand and model because they change the designs and the chamois so often. Also, I hate paying full retail for shorts so I look for deals when I can. That said, I think I paid full retail for the Aerotech designs shorts and they did seem honestly priced at $50, and as good as a lot of brands that retail for $80, then discount down to $50.