How do I select a color to paint various rooms in my home? What color guides are best?
I agree with ChrisF's comment that this is subjective. I doubt you'd share my love of bright fuchsia with lime green trim I have in all my rooms. 

That being said, Behr's "Paint Your Place" is a tool that allows you to pick colors and add them to a picture you've uploaded to get a better idea of what the finished room would look like.