You'd probably save money by buying your MacBook with the cheapest harddrive available and then buying separately a high-speed drive. For example, you can buy a WD 320GB 7200rpm drive at Newegg.com for $60, or a Seagate 500GB 7200rpm drive also at Newegg for $75; upgrading from a 320GB 5400 to a 500GB 700 at the Apple store costs $150 EXTRA. Just swap the drives (very easy on current models, there are plenty of guides online), stick in the discs that came with your computer, and install, and now you have an upgraded hard drive, extra cash in the bank, and an extra hard drive you can use as a backup, an external storage drive (with a $20 adapter), or you can try to sell.
ifixit.com has awesome guides: http://www.ifixit.com/Guide/Browse/Mac
I get 90% of my computer stuff at http://www.newegg.com
because of great selection, good return policy, and great prices. If you don't like buying online, there's always Fry's, Best Buy, and local shops.
Edited by Jaguar45, 21 July 2010 - 06:26 PM.