Two songs named Gravity...
One is from an up and coming artist - Sara Bareilles.
The other from an official AnD artist - Vienna Teng.
Sara Bareilles toured on her own for six years until one day a youtube clip someone shot of her ended up going viral and caught the the attention of a much wider audience. I think it's a great lesson in the idea that you just make sure you're totally ready for when luck finally strikes. If luck strikes too soon, it's not always a great thing.
Both are vocal/piano arrangements and both are quite nice. I'm sharing both audio only and youtube links because... the audio on youtube is just not so great it also gives me a context with which to mention www.seeqpod.com which is a pretty great website. I don't know much about how ethical it is - but it's a great source when you're looking to find and share music.
SeeqPod - Playable Search Video: http://www.youtube.com/watch?v=1IQZx1xvWUI Video: http://www.youtube.com/watch?v=BJbip5Wk3_Y