I propose a resource system where:
you build up your pool of resources by being connected to that resource
when building something with a resource, it takes away from this pool
So if you have iron, your iron supply would build up (picture the food collecting before a city grows) as long as you were connected to it. When you build a swordsman, it would cost 30 shields and 1 iron. If you were connected to two irons they would build up a lot faster so you could produce a lot more swordsmen.

For luxuries:

you build up luxuries in the same way as resources
you set the amount of luxuries you want to use for happiness, and the amount you want to save in your pool
each luxury in your pool would be enough to keep a certain amount of citizens happy when used
As far as trading is concerned, you would trade a set amount of resources/luxuries. So in the trading screen you would say, I need 30 dyes and you'd negotiate a deal for them. Then when you ran out you'd go back and ask for more. You could have caravans (http://forums.civfanatics.com/showthread.php?t=101488&page=1&pp=20) deliver the resources/luxuries too (shameless plug).

I'm a huge fan of this. Yes, yes, and yes.

A key, of course, is that people shouldn't be able to get really far ahead by monopolizing a resource. There should be a LOT of resources with a lot of different functions, so that everyone has a piece of something important.

And if there are ever too many resources to keep track of, certain old resources could become obsolete. (e.g.: discovering steel, discovering plastics, discovering metallurgy makes old resources like limestone and clay completely replaceable).

This would make resources more important and more strategic without upsetting gameplay balance.

I like that resources are just like shields in that you need a certain amount of both. I also hope that they can't be monopolized easily though you may not have much. I had a problem in that there weren't enough of a type of luxury so I couldn't even trade for all 8. I hope that can be remedied as well. I also hope that you can trade for like 10 units of iron lump sum or per turn rather than just iron. It would add realistic strategy.

Wait.. so everyone likes the original idea so far.. that isn't right.. http://www.chatcity.com/images/winking.gif

The other thing I was thinking was where the resources would be stored. Would you have to build a granary like city improvement, say stables, to store all your horses or is it automatic. The other thing you could do is, if you had to build colonies (http://forums.civfanatics.com/showthread.php?t=101680), the resources could be stored at the acutal colony. I dunno, just automatic would probably be the way to go because it would be easiest.

Yeah, not like gold needs to be stored anywhere. And if a city is looted, it automatically takes a percentage out from the overall treasury. By all means, the same would be true with someone's oil supply. ... maybe put a little bit more weight for cities that have oil within its radius.

I am definately a fan of requesting certain resources and luxuries as an option during trading. If I have something, and y civ requests it, then I may want to trade it, esspecially if I was offered xxx gold for that resource. I could forgo a few rounds or once off sales of that resource just so I could increase my capital at a time when the resource isn't needed.