Hi shadow soldier. You'll find all "80 Gig" drives , whether fitted to Apples, IBMs or the clone from the backyard dealer down the road, or even straight out of the Western digital , Seagate, Maxtor or whatever store room, actually have about 74 Gigs of real space.
The problem occurs because of the way disk manufacturers calculate drive size.
Your computer OS measures "Gigs" on the basis of 1024 bytes = 1 kilobyte, 1024 kilobytes = 1 megabyte, 1024 megabytes = 1 gigabyte.
HD manufacturers , however, use a straight 1000 bytes = 1 kilobyte etc (following the normal coventions used in the metric system rather than the computer industry's general, but non metric, system).
In essence, an 80 Gig drive , using the HD manufacturers approach, will have 80,000,000,000 bytes capacity, which converts to around 74 Gig if you divide 80,000,0000 by ( 1024x1024x1024) .
The rest of your missing space is mostly taken up with things like GarageBand and iDVD templates and "loops" etc. Some more goes into the "trial" versions of iWork and MS Office. THen come the other applications and finally the OS itself (including langauge localisations for many places that you may not even have heard of!).
By getting rid of things you don't want or need you can free up quite a few gigs of space.
I am awaiting my MB at the moment, and i am going to order a 100GB 7200rpm drive to replace it with from Newegg.com, I am thinking Hitachi, but can anyone give us some input on maybe what the best drives are, in your opinion of course, just so i can gauge what it really might be. I still have about 2 weeks to wait before i get my MB so i have some time to decide. Hope my info helped some of you and that yours will help me!!!!