Hi jiro, and welcome :)

For the textures, well I have a huge photo's collection I've made myself sine 10 years, and ............. no that's wrong :P
Just go there -> http://www.cgtextures.com/

For the gear I'm just using this one,



The same image is used for the diffuse color, the diffuse amount (but with a different projection scaling), and for the bump.

Then I do a little compositing in photoshop.



Image 1: color diffuse Image 2: Specular boosted Image 3: Ambient occlusion

So I mix the 2 first image with a mask, to have variation and more specular in frictions area. I can use a vertex map to mix them directly in the surface editor, but as I'm doing a still image I don't care and I paint the mask in photoshop, it's faster :)

The last image, the ambient occlusion pass, is used as an overlay layer to boost the contrast. (it's a cheap dirt layer)