The hardware that I put in my parents' computer is dated to about the same age as your system. Putting the SSD in theirs brought new life to that system like you wouldn't believe. I'm a firm believer in SSDs for the OS drive. The bang for your buck that you get (versus upgrading all components) is outstanding, and they've really come down in price.
I'd strongly recommend the Samsung Evo
. It's a few bucks more, but very popular and very speedy. Grab the 250GB if you're only going to be running one drive in your computer (OS + storage), or just the 120GB should do if you only want to put your OS and programs on it, then keep your actual files on your current hard drive that's in your system now.
Intel Core i7-2600K @ 3.4GHz || GIGABYTE GA-Z68X-UD3P-B3 || Corsair Vengeance 16GB DDR3-1600 || EVGA GeForce GTX 480 || Samsung EVO 256GB SSD
my feet get cold and that gives me diarrhea sometimes - Smart_Guy