considering that macbooks use SATA HD(i guess the proper name is ATA150, but idk) and most of the market is ATA (IDE, or i guess ATA-6) im thinking that you have things mixed up. The reason that ATA-6 has so many hard drives is that they have been out longer than SATA and use tried and true technology, which is why they can fit 160GB in ATA and only 120GB in a SATA. most of the new computers are starting to switch to SATA. so this entire post could be shortened to SATA =newer = less market = less storage