In Civ4, the valuable resources are all practical. Iron and Horses for units, Marble and Stone for wonders, these are the resources to fight for. But historically there's been another magnet of human greed, one that deserves a great deal more benefit than an extra happy face in each city. Precious resources like Gold, Silver, and Gems should be made more desirable. Historically, economies have been built on these resources. They should therefore be given a more economic role in the game, perhaps slowing the rate of inflation or even just giving a flat bonus to wealth. One shouldn't need to own the mine in order to get an economic benefit, there should be reasons to trade for it. Any ideas of how to make gold more relevant?