Tweety: Thanks for the suggestions. Regarding dirt and grime, is it best to have these elements more or less isolated so they can be layered on? Or does it really matter?

Dave: Do you mind sharing why they're useless? I'm looking to focus on things that are difficult to create proceduraly (is that what you mean by PS with filters?) Agreed on the specularity, the idea is to minimize or eliminate highlights, shadows, reflections, I guess anything that is contributed by things other than the color map.

Dom: I know cgtextures is a great resource, so it'll be difficult to compete (and with others), which I'm not trying to do, but I'll try to get stuff that isn't available to the same degree elsewhere... which is partly why I'm asking for suggestions. Ring flash.... ha, I wish... I'll just use cloudy daylight in the meantime.