The blending modes I used the most are “Overlay, Soft Light, Luminosity, Hue and Color”.

I ussually use they with textures, but also to make shadows and lights in my compositions, like in this “How it’s Made”: http://img189.imageshack.us/img189/7563/anigifvhj.gif

I’m seriously addicted to blending modes… the first thing I do when I import an image is to make a B&W adjustment layer, and flip it to Soft Light. It gives me a great sense of what the luminosity levels are like through the image. Lately, I’ve been using Vivid Light and Hard Mix alot to (along with Color Burn and Color Dodge).  I  found out that ‘Fill’ reacts differently with these blend modes than ‘Opacity’ does… so if you add Hard Mix, and lower the fill to 15-30% you get these amazing color changes (mostly intensifing color), then you can lower the opacity to reduce the effect as usual. I can never remember exactly which blend modes behave that way, but I know Color Burn/ Color Dodge, Hard Mix and Vivid Light got MUCH more useful when I started playing with fill.

I like them all… But one useful tip that I think its nice is using the Difference mode to align similar layers. What the Difference mode does is to turn black the same pixels underneath it… so when the image is perfect aligned you get a black artboard, than you flick back to whatever blend mode you want or whatever.

Totally Nicola, you can use either method for making a layer less visible in the lights and darks, good point.