I love Garageband. ridiculously easy! (I don't have the latest version though, and to be honest I wish I could go back to the one before my current version). I found drum loops a bit of a pain though, I could never get the feel I wanted. I eventually bought an electronic drumkit and that is perfect. I play keyboards first, altering tempo as and when I feel, then I drum along to that, and add everything else afterwards.