I just bought a ticket on Orbitz for over $70 less than the USAir site for the exact same routing - this isn't the first time this has happened - anyone have any insight as to why?

1K miles sure isn't worth $70 cash!

This is very common. It often happens on Expedia as well.

I think US Airways allocates certain discount seats on usairways.com, Orbitz and Expedia. The discount inventory is not consolidated in the real-time. I often found that when Orbitz had a lower price ticket and usairways.com didn't in one day, the next morning the low price ticket would show up in usairways.com as well. It rarely happens the price differences will persist for consecutive days.

Been discussed a few times here, but basically airlines who use orbitz can either pay a $2 million annual fee or agree to provide $2 million worth of cheaper tickets. Its alot easier to just slide over some cheapos every once in a while than pony up $2 mil in cash...