Adjusting your photographs to get the color 'just right' can be a chore. Think about this: The Old Masters of painting spent years of their lives learning about color. Why let all their effort go to waste on the walls of some museum when it could be used to give you a hand with color correction?
When Photoshop entered the CS series it included a new tool called 'Match Color.' This tools was made so that you could match a series of photos to one another.
But there is another thing you can do with 'Match Color' that is much cooler: You can match the colors in your photos to those in famous paintings.
I keep a directory of about 30 of my favorite paintings and anytime I need to do color correction, I just scan through them to find the one that gives the photo I'm working on the best look.
This technique can be used in other ways. For example, use the color from a scanned-in 1970's Kodachrome snapshot to give a recent photo a vintage look. Need to make a picture more menacing? Use the color from a picture of a storm.