I tried those cycling shorts, but I just couldn't live with the fact that it felt like you'd shit your pants
The most comfortable bike I've ever had (by a coutry mile) was the FJR1300 (07 model). Never ever had any problems no matter how far I rode in a day. All other bikes have given me trouble on long distance runs.
For me, the problem comes in warm weather and it's not so much numb-bum as pain just below the bum cheeks (don't worry, I won't get any more graphic). I find that the heat from the bike, the ambient temperature and the heavy protective clothing on a vinyl seat all contribute to making me perspire; the end result being that my skin is sticking to my clothes and you get this dragging feeling on your upper thighs as you accellerate and brake. It's
that that causes me discomfort.
Tom