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You also learned that finally even Adobe recognise the importance of The Rule of Third in photography. The crop tool in their latest Photoshop CS5 Extended will superimpose a "Third Rules" over your to be crop image, hopefully guiding you to a better composed crop.
The only problem I find about those very fine overlay lines, they are a bit hard to see; wouldn't it be nice if we can have easy to see white lines and we are able to overlay them to our image anytime we want?