Apple has pulled one unexpected rabbit out of its hat today, the Apple Fusion Drive. It's a combination of SSD and HDD technology. Fusion Drive is part of the new iMac just announced, and is a technology supported by Mountain Lion. In concept, it's similar to auto-tiering that is used in enterprise environments.
In practice, Apple is offering a 128 GB SDD with a 1 TB or 3 TB HDD drive that are combined with smart software. The OS will monitor which apps you use the most and runs them from the SDD. Apple claims that, when the system is idle, it uses 50 percent less power than a standard hard drive.
No word on whether this tech will hit other Apple products but it's logical. I'd love to see external drives with this configuration as well.