You can also reinstall OSX with the options you like (Bottom left is the button to Customize when you install, after you agree to the license). Get rid of all the extra languages and printer drivers/demo soft, and you get back some good GBytes. I did that 10 or so minutes after I got it up and running the 1st day.
Basic OSX and some interesting program from darwin ports, gives almost 70 Gigs free.