Why not upgrade the whole shebang? Image/video quality should be of utmost importance in a surveillance system. Since you have low rez analog cams now, I'd upgrade those before anything else. Then you can post stuff like this to youtube:
http://www.youtube.com/watch?v=C5uIH0VTg_o
We are actually upgrading the whole system, thats my main role here but the old system still has coverage in a few areas. That and the old system still has value so the plan is to give a overhaul and sell it with all the old cameras.
I think most people are assuming that the point of the system is recording the video onto the HDD.
If that is the case then if the HDD goes down it is irrelevant whether the SSD is still working as you're still not recording the video. Using the SSD for OS would also not lighten the wear on the HDDs either, extremely trivial compared to the constant video recordings. By having two drives you're actually significantly reducing reliability because you're vulnerable to 2 drives instead of just one.
That is the point of the system but if the HD containing the video is down all you are out is a couple of weeks of video, assuming you cant recover anything. Worst case scenario is you pick up a new drive, format and you good to go. If the OS drive goes though you are totally down counting on having good backups, a scary proportion knowing some people.
I ended up going with a Patriot Torqx 2. I know its pretty slow drive but I havent heard of any issues with the Phison controller as far as reliability goes, and Patriot has a pretty good warranty and support. I just couldnt see dropping nearly $100 on a Intel drive. Im begging to 2nd guess my decision though, hopefully I didnt make a bad choice, I wish I had seen that OEM Samsung before I had ordred.