What pressure should I run? Front versus the back wheel?
It depends on the terrain you ride on, what you find comfortable and so on, so you need to play with tire pressures to figure out what fits you. Several companies (e.g. Schwalbe) give recommendations, but they're only good to start -- you need to play with tire pressures to find whats good for you. 

The number written on the sidewall of the tire is generally useless. For most riders, a correct pressure is significantly lower than whats written on the tire sidewall, and the tire sidewall rating does not take into account the strength of the rim (wheel) you're running, so blindly obeying it can be hazardous since the rim may take damage if you hit a bump at max pressure. A correctly inflated tire absorbs road hazards appropriately and avoids pinch flats while not having too much rolling resistance. 

That being said, a rule of thumb is that the rear tire is about 10% higher pressure than the front tire. But you're completely free to ignore this and find something that's comfortable for you.