Let me just say that Pandora is one of the greatest inventions ever! As I type this, I am listening to a station of Billie Holiday, Louis Armstrong and Ella Fitzgerald. My music tastes are wide ranging and eclectic so I love being able to make a different station for every mood. It is a great way to find new artists and explore a genre without having to purchase a lot of music only to find I don't particularly care for it after all.
Google Earth is not only fun to play with, it can also be very useful. This is not really library related, but I volunteer for an animal rescue and Google Earth comes in handy when screening applicants. Unfortunately, people are not always honest so I can use Google Earth to make sure they actually do have the fenced in yard or acreage that they claim. That is just one practical application of this service.
I was not familiar with Google Book Search until very recently, but I am quickly becoming a big fan. I was shocked by how many books were available. They are easy to browse by topic as well. For example, I am interested in the Social Sciences so I can click that category to find a whole list of books that might interest me. I can read an excerpt to decide if I might be interested in purchasing that particular book. I can also create my own library of books I've read, my favorites, books I would like to read and books I am currently reading. I could get carried away with this application, particularly when creating my "To Read" list!