I just wanted to point out to anyone interested that the Garage Band acoustic guitar sounds IMHO awesome. It even has some subtle finger slides/rubbing sounds which really bring out the realism. I believe this is the standard acoustic that comes bundles with garage Band (I do have Jam Pack 1 as well, but I think it's from the built in library).
Pull it up from the Channel Strip, click on the word "inserts" and select Acoustic Guitar. It will not only pull up the instrument, but also a great EQ set up that really makes it shine.
IMHO this sounds better than many other high priced offerings, and if you have Logic and Garage Band, chances are you already own it!
I bet you never even thought of pulling up those Apple sounds! I bet there are other jems to be found too.