You might want to read this about the SSD.
http://en.wikipedia.org/wiki/Solid-state_drive#DisadvantagesI was considering the same thing for my notebook, since I use it in my truck with all the bouncing up and down and vibrations. But, I do a lot of file transfers, and I do mean a lot, and I didn't like what I read about the SSD after so many writes performed on it.
With that said, the SATA III will more than likely be in the form of SSD's only. Since they are going to be built for speed and lower power consumption. Don't get me wrong, SSD are great, but they are made for the consumers that do low to medium read/write situation. If you do high to very high, you might find yourself replacing sooner than expected. Not saying in a few months or even a year, but considering how long a regular hard drive would last you, its a very short life.
Even if your still considering to get a SSD, the other thing to consider when purchasing one, which one you should get. Me, myself and I would suggest the flash based one, because if your storing important files on it, it doesn't require continuous power to be feed to it. DRAM SSD's will need power feed to it at all times to keep files. Which is a important fact most consumers need to know.
If there is something I'm missing or thinking wrong here, let me know, I only know what I read and read a lot before deciding not to get one when I built this notebook and choose to go with the hard drive I have now.
Ok, done being long winded for now.
Thought I put my 2 cents in about the SSD's since you brought it up.