I used the paint recipe from Warhammer TV's "How to paint Custodian Guards" as a guide for my Adeptus Custodes. I departed from the stock colors when painting the metals as you'll see below. In these cases I had plenty of Vallejo metals, was comfortable with their use and find they put down an equal or better effect on the models. Also, the small amount of black was done in the same manner as my Deathwatch recipe since I am most familiar with it at this point.
Primer: Vallejo Black Surface Primer (74.602)
Final seal coat: Model Master Lusterless (Flat) lacquer
Gold Power Armor
Weapons & Equipment (metal parts)
Weapons (gun casings)
Weapons (ammo shells)