Just a thought, but I'am thinking of upgrading to a SSD. My question is would I notice any difference in game performance? OS on an SATA 2 HDD and games on a SSD?
All views welcome!!

Loading of resources is faster, even for an OS

Iam looking at a corsair M4 128 GB for $109.99 brand new in the box. So If I keep the OS on the SATA and games on the SSD (old drive was a ATA133). Then I will lessen my loading times?

Yes. The OS won't be any faster unless it too is on the SSD, though

Right on!

If you meant a Crucial M4, it's what I currently use and it's a solid and fast drive. Be sure to upgrade to the latest firmware, which can be found on Crucial's website. Your mainboard has SATA2 ports though (3GB/S) so you will not see the maximum speed that this drive can achieve as opposed to a SATA3, but the performance improvement will be quite noticeable nonetheless.

I use an SSD for gaming and an HDD for the OS.
If I could put up with the hassle involved I would use another SSD for the OS...

Not so much a performance boost, but you'll see quicker load times for OS and games. Also games like skyrim that load and stream will also load areas quicker. An SSD should eleviate the little blip you sometimes get when a new area/grid is loaded.

One other thing to Remember with SSD"s is if you are using First gen sata 3.0 (EG: Asus Rog3) you will get better speed off a 2.0 due to the marvell drivers the 3.0 utilizes.

If you get a decent SSD, it will drastically improve your loading times, but it won't improve your frame rate, perhaps very slightly if you are using high res texture mods, etc.

But you must install your OS and the game (including, of course any mod files) on the SSD.

Loading times and pop-in were reduced when I got my SSD, my rig is in my sig, OCZ Agility 3 60GB is the SSD I use. Helped my loading times with the HD Texture Pack.