So when I'm often asked "where do you get your quick inspiration from online?," one particular design studio's site that comes to mind is www.fwis.com. Not only is their gallery chock full of motivational imagery, but they also feature a blog called "Covers."
Book cover art is featured and updated several times a week and open for commenting. I like to think of it as a virtual wall meeting where random viewers can critique the art director's motive. Check it out, and let me know about your own favorite "quick fix."