I use 2 seperate drives. Windows is on the SSD and when I install a program I put on my D: which is SATA drive.

I run a 256GB SSD for my OS plus programs & my storage plus Steam drive is a 1TB Raptor drive both sitting on Sata 3.0 for great all around speed. SSD cache will only speed up some programs (your most used plus boot), I wanted something that increased the speed of everything.

Oh, you should know that SATA 3.0 is not faster than SATA 2.0 WHEN interfacing a HDD.  The Rotational speed of the HDDs is much too slow for any speed up.  Even the Raptors maximum sustained Read or Write speed is 180 KB/s or just a tad over 50% of SATA 2.0 data rate. 

Personally, I like SRT and I've been running it since this board came out with no issues.  It's transparent, the speed boost is nice even though it's not quite as fast as running pure SSD, and I don't have to worry about shuffling game installs between the magnetic and solid state drives.
 
I made my system with the entension of using SRT so I only bought a 64GB drive which is Intels maximum recommended size.  If you bought a larger one, I would partition 64GB off that and reserve that for SRT and then use the rest to install your OS on.
 
Or not, it's up to you. I just think that not having to think about where to install or move game installs makes up for the slight performance gain of going pure SSD.

Personally I am currently caching with a 60 GB Agility and a Western Digital green (slow drive) all of my programs and Windows is install on the green.  After opening programs the second or third time it really does feel like SSD speed, especially when opening programs like Photoshop and Illustrator at the same time and it only takes about 2 seconds.  I never turn my system of so the really fast boot times when having Windows installed on the SSD does not matter to me.  The main benefit of having SRT would be space and management,  SRT caches your most frequently used programs and moves the less frequently used to the bottom of the list and eventually will drop off of the cache.  In my opinion this is better compared to having Windows and programs installed on the SSD.  Mainly in the case that you have a full SSD and you have a new game or program you want on the SSD, you will have to remove something to make room for the new application.  With Smart Response Technology this is all done on the fly for you.  Past that everyone here has great suggestions on which they feel is better it ultimately comes down to what you think would benefit you best, either way performance is great once you add a SSD in either configuration.    Lately with the prices of SSDs at the higher capacities it is starting to make it more reasonable to have a SSD without caching.  If you have any questions on setting it up please feel free to contact us.