I recently fell in love with the film (500) Days of Summer. I've become totally obsessed with the soundtrack, as well. Lately, the song "You Make My Dreams" by Hall & Oats has been on constant repeat, driving nearly everyone in my house (pets included) mad.
It's the catchiest tune ever written. I can't get enough of it. I listen to it easily every day, and more than once. The beat is so fun, and makes me want to dance every time I hear the opening measure. It's the only song that literally puts an instant goofy grin on my face. The way that it's composed makes it a perfect balance of pop fun so that it's not annoying, and it's also interesting to listen to. As musically wonderful it is, there's no way you can sit still and appreciate the instruments because you're too busy jumping around and dancing and smiling. It is the song to lip-synch obnoxiously to, and that's something that makes this song as extraordinarily fabulous.
Everyone should start their day off with this flawless tune: