Earlier this fall, fed up with being wet after riding (commuting and MTB - although I try to avoid riding in the heavy rain for ethical reasons) I went and bought myself some shorts.
I started out with a pair of Sugoi RPM-X waterproof shorts ($95 MSRP), they were on sale so bonus, they also seemed to fit well. Then I received a gift of a pair of 7mesh Revo short ($275) a couple of months later - I wouldn't have otherwise acquired such fancy riding shorts, after using them, I'm convinced that they are entirely worth the asking price.
2.5 layer laminated fabric, seam taped, traditional short construction
The Sugoi shorts are waterproof and they work well at keeping you dry. They have a velcro closure at the bottom that helps keep water from riding up. I, however, found them to be too short - riding up mid-thigh during pedalling; this resulted in my legs being cold and wet on the uphill and then the knee pads being wet on the down. Also, when using them for commuting on colder wet days, my sub-layers would get soaked. The only real benefit was that the chamois would stay dry, which is nice. I believe that these would be a fantastic value oriented short if they were cut/available in a knicker style. Sugoi does make a pant ($145), and in retrospect, I might have been better off getting that and having my wife hem them into a knicker as I am not a fan of riding in full pants.
Gore-tex 3 ply, seam taped, no seam down the bum
By being longer and draping over the knee, the Revo shorts address all of the issues that bothered me with the RPM short. Now, my commutes and mountain rides are dryer down past the knee (shins don't care) and I'm comfortable in them for everything but the most extreme downpour - in which situation, I likely shouldn't have been riding anyways. I also find that I'm willing to be out in the elements for longer periods of time wearing these shorts as they breathe well and are comfortable to wear. I echo Cam's review linked above, they've made wet weather jaunts far more enjoyable and made my commute to work on wet days far more bearable.
"I know that heroes ride bicycles" - Joe Biden