Roc is a free online music creator by Aviary, one of the nicest suites of online tools. Roc has a bit of learning curve but once it is learned it is a very detailed site for creating some excellent music.
If I would've known of this site a few days ago I would've included it on my top 10 list and probably listed it at #4.
I highly recommend checking out Roc by clicking here.
Thanks to Larry Ferlazzo for the heads up!!