An online radio (that doesn't work in anywhere in the states which is why I don't like it) that can play music similar to your tastes.
Like if you searched Jason Mraz there's a high chance you're going to get Colbie Calliat or if you searched Vanessa Carlton you're probably going to get Michelle Branch.
Jason Mraz has gotten me Colbie Caillat, Regina Spektor, The Beatles, Train, Eric Hutchinson, James Morrison, O.A.R., Three Doors Down, The Goo Goo Dolls, Five for Fighting, and a whole host of other artists that I adore. ^-^