Also, I was curious if this is only a recording program? Or, if u can plug in an mpk or other midi controller?
if you buy a new mac, the iLife applications are preinstalled, but if you upgrade your Mac OS X, this will not install the iLife applications.
GarageBand is much more than a recording program. It is designed to record audio and midi,and to mix and to arrange songs. It comes with plenty of software instruments to be used with midi tracks, with audio filters, and loops (rhythms, world instruments) and sound effects, stomp box effects for your electric guitar.