I never been a mac user but to answer ur question i had a look on the system of a friend of mine who have mac and he seems to have a large hd ore than 10GB as i saw..
also in an ad i saw a poweribook(a protable mac my dear) or something like that.. with g4@1ghz and a large hd.. but's it's enough hard to manipulate in the begening..
i.e: to install a printer me and my friend had to install the port first because it was not detected and then the cable.. and finaly the printer which took us all night we finaly slept at 6AM..
Have fun..