Depends on the tire..
I've used a lot of different tires and they differ as to psi. I weigh 195-200 (winter) and I inflated my Conti GP3000's (what I usually ride with) to 105 F/R. I was running 120 and slowly dropped my psi over a long period of time after reading Uncle Al's article on the RoadBikeRider.com newsletter a couple of months ago. I recently installed Vittoria Open Corsa EVO CX's and I started out at 110 and they felt fine. I dropped to 105 and my rear tire felt real squirrelly on descents (like I had a flat). I checked the sidewall when I got home and they listed the psi rating as 8.5-10 bar (115-145), so I inflated back up to 115.
I think the inflation level you set your tires at has a lot to do about the brand of tire, your body weight, the type of riding you do, and the types of roads you ride. I don't think it's one-for-all.
Another factor to consider is the gauge on your floor pump, most are not accurate. My old Blackburn pump was 5 lbs under the indicated setting. You should take the time to calibrate your floor pump and adjust accordingly.
I noticed that riding with a lower psi made my bike ride better and my tires last longer. You have to experiment. I started by dropped my psi 5lbs a pop and over a period of months until found what felt best for me.
But like I mentioned not all tires are the same. I just installed new tires on my Ford F250, switched to a different brand (same size) and it rides like a different truck. Bike tires are the same way...