SALSA GORRRDAAAAA!!!! If you want to shake away the sadness of a rainy day, put some salsa and dance until you can't dance anymore and you'll see you won't notice when it stopped raining!!!
A good song for a rainy day well for me that's "Rainy Days and Mondays" by The Carpenters..as for genre I particularly don't mind what I listen to anytime but if I had point one out it would have to be Easy Listening!