If you think it's necessary, go for it. Dual Core gives you some stability in the newer XP releases, and if you update to Vista it'll be a great speed/stability increase.
But not many games use it. I think Oblivion does though. It won't make the game any prettier, though, but it'll stabilize framerate.
HOWEVER, as that is a LightScribe DVD, look over the drive (Google Search) and make sure it is compatible with the DVD medium you are interested in buying (The cheaper ones), because LightScribes are sometimes VERY picky when it comes to disc burning.
Nothing like buying that 30 dollar 100-DVD spindle, thinking you have a SEXAH deal, just to find out your lightscribe doesn't burn te discs...