Since tire pressure is being discussed, allow me to point to a neat chart I found years ago (posted here) when I was trying to minimize the impact of road buzz on my hands.

Rather than as "ideal" inflation, I've used this chart as the minimum tire pressure I can get away with given my weight and the bike's. In tend to go close the maximum PSI for my rear wheel (120 psi is what my tires can take), but I go closer to the lower inflation suggested by the chart in my front wheel.