We have seen many hybrid drives come and go, most of which only benefited desktop users who were accessing certain files often enough that they were cached on the flash memory.  Seagate has introduced a new iteration of the SSHD specifically for laptops, uniting 500GB of 5400 RPM platter based storage with 8GB of MLC NAND and a 64MB cache which [H]ard|OCP recently benchmarked.  They didn't forget desktop users as they released 1TB and 2TB models at 7200 RPM but it is the laptop version which is perhaps more interesting as not many models allow the installation of a second drive like desktops do.  The testing results were mixed, with several obvious benefits interspersed with odd performance changes after multiple runs, however the small price differential between a standard HDD and a SSHD might just convince you to pick up this new breed of hybrid drive.

"Seagate has introduced the next generation of Solid State Hybrid Drives, commonly referred to as "SSHD." These drives use a small amount of MLC NAND to accelerate the performance of a 5400 RPM spinning disk. Today we test the mobile version against other available SSD caching solutions."

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