Get an iMac loaded with GarageBand 2! :)
(Sorry, as a long-time Mac-user, I had to say it!) But seriously, for user-friednly recording software that scales up well (to a point) and comes chock full of ready-to-use loops if you want 'em, GarageBand is actually pretty tough to beat, IMO. (For more advanced stuff, I might try Cubase SE or whatever the "lite" version of Cubase is called.)