That rainymood site is awesome.
First I played my typical rainy day music, then I decided I'd try something that had a section where the instruments dropped out to see how it sounded with the rain. I naturally thought of "I'll Make a Man Out of You" from Mulan (It had been on my mind, anyway--'twas in my dream). It's so sweet. I happened upon catching a thunder crash right on the line "But I'm fire <crash> within." And, the rain for "We must be swift as the coursing river" is so cool.
My roommate's listening to his techno dance music now with the rain in the background. He likes the addition, too.