Alclad II paints are awesome and very addicting. I use aluminum, dark aluminum, dull aluminum, steel, stainless steel, polished aluminum, chrome, pale burnt metal (good for carbs that are light goldish color)...pretty much all of them.
I agree with the posts above, too - mix all the finishes for a convincing look.
Here is a model I am working on now:
And under:
Most of the "metal" parts are Alclad II.
This model is actually almost all Alclad II, even the frame:
You can't go wrong with any of the colors...