If you hVe the money go copper. There is nothing I dread more then working with black iron but if you don't mind the headache then go for it. Stay away from PVC though, ohsa gets a few things right!
What is so hard about iron pipe? If you get it at Lowes they will cut and thread the lengths you want, then you use a T where you want an air connection and then continue to the next connection. I do recommend the drops that have been talked about. I always put a bleed off valve in the drop so I can drain any water that might get trapped there. I also use a water trap/dryer and an oil trap in the system. I still need to do my current building.
