Audio Editors equivalent to Apple's GarageBand?

I've been looking high and low for something comparable to Apple's GarageBand that is free (as I am already paying an arm, leg, and a shaft up the ass for video editing software and hardware). For those of you who don't know what GarageBand is, essentially, it is a user-friendly, all-in-one, audio editor for mixing, editing, and creating music and sounds for the Mac. It has hundreds of pre-installed beats of every type of midi sound, as well as interchangeable instruments between beats.

I've seen Audacity, however, it seems to be a bit lacking of the midi instruments I loved in GarageBand. I was hoping someone might have had experience with various software. Any help is appreciated. Thanks.