I run my front around 115-120 and my rear at around 130-135 on Bontrager Race Lite's. I weigh 157 and my bike weighs about 18 pounds. Of course, I'm 17 and my body can handle road vibrations and such that would leave sometime 3x my age crippled for a week. I haven't had many grip issues, but I don't race either, I'm planning on racing some crits next spring, and imagine that I'd run a lower pressure there for better cornering.

I generally use the visual deflection rule more than actual pressure. If I get 2-4mm's of deflection when I lean on the tire, I roll out, unless its a recovery ride and I want a slower, more comfortable ride, then I let it slide down to 4-8mm's. It all depends on how much comfort you're willing to sacrifice for decreased rolling resistance. I know that at this point, I don't see myself running anything below around 110psi, front or rear, unless it's a rainy fall day with lots of leaves on the road.