I learned the (very) hard way... do NOT use liquid soap when washing your bike shorts. The soap does not rinse out completely, especially in the thicker pads/gel pads. I was always so chaffed until I figured out what was causing it. We go on Mtn Biking vacations every year to a different place and am on the bike everyday for hours. Currently, I have PI Micro shorts which I love and they are extremely comfortable. They have the grey, ribbed pad and supposedly it add some ventilation. Now I'm in the market for another pair of shorts and will definitely check out some of your suggestions.
Happy biking!