I found a great little filter for Photoshop that makes extracting images from the background that is quick and easy.
It's called Re_Mask 3 from Topaz. ReMask gets the job done in a shockingly short amount of time, while requiring a bare minimum of your input. No need to go through all kinds of steps, just quickly paint image features to tell ReMask what you want to cut out, hit the compute button and it's done!
I use it to replace backgrounds, especially when I need a perfectly white background, reposition subjects, and create compositions. Give it a try and see if you like it:)