He's referring to Intel's Smart Response Technology. It's part of the Z68 chipset and it allows you to use a SSD as a cache drive instead of a logical drive. The difference is that as a Cache drive it'll speed up all of your most commonly used applications regardless of what physical drive they're present on (typically your HDD). As a logical drive a SSD can be used as a boot/application drive but only the programs that are installed directly to that SSD will see a performance boost.
SRT = boosts most common used programs, is an install and forget solution.
SSD as Logical drive = better performance, only speeds apps you install to SSD, can be a pain to micromanage.
With that being said, SRT only supports up to 64GB of storage. So if you buy a 120GB SSD you can use the remaining space (56GB, give or take a few for formatting) as a logical drive to install your most important apps on.
Typically if someone wants to go the SRT route, a MLC drive (google MLC vs SLC) isn't the way to go because caching by its very nature is very write intensive and MLC drives have a limited number of write cycles on their nands (the flash memory used for storage on SSDs). It's still up in the air as to if this is a legitimate concern or not, but to give you an indication OCZ recently released a cache SSD in which they provisioned half the entire drive just to act as a redundant shadow to minimize this effect.
If you want to avoid this issue all together Intel has a 20GB drive, the 311 for $119. The main difference is this drive is SLC which isn't impacted by write thrashing nearly to the degree that MLC drives are. While it's only 20GB, it's more than enough to act as a Cache in SRT.
By the way, your motherboard doesn't have a SSD built in. It has SRT, which is the ability to use a SSD as a cache disk.
I know this is all alot to take in, so if you have more specific questions, feel free.
edit: The Vertex 2 is a gen2 drive. Current drives are Gen3 and are about 2x as fast. The Vertex 3, Patriot Wildfire, Mushkin Chronos are examples of Gen3 drives. While you can use a Vertex2, and do it at a legitimate savings, just keep in mind that while it's still going to be much faster than any HDD out there, it's considered slow versus the ones I've mentioned.