Opinions on system build

It's pretty weak for everything except generally use. For gaming, you're being held back a lot by the GPU and CPU, depending on the resolution of the monitor. If it's fairly high (like above 1280x), you're being held back a lot by the GPU. If it's at lower resolutions, you're being held back by the CPU.

The CPU is restricting you in any other non-gaming, heavy use application (rendering, video/photo editing, encoding, etc.).

Since you're looking more at gaming at it's main use, I'd seriously consider dropping in at least an HD 5770 ($100-125) or a GTX 460 1 GB ($175ish). Those will drastically improve your performance. However, you'd soon be constrained by having a dual core CPU, as more and more games are begining to make use of quad core CPUs. You could spend another $70ish for an Athlon II X3, or up to $145 for the X4 955, but you should be alright for now as long as you limit background activities while gaming.

I have read about unlocking the 560 to a quadcore is it worth doing that

A 3.3GHz dual core CPU isn't that bad, but depending on your resolution, visual options and games, the 9600GT could definitely be your biggest bottleneck. I think the x2 560 is a unlocked "black edition" isn't it? If so try to OC to get more out of it and it shouldn't hold you back to much for gaming.

I agree with MadAdmiral if you were going to build that at least get a better board so that you can upgrade later on if you want to. You are going to be severely limited with only one pcie 2.0 slot and only 2 slots for ram. Would reccomend JetWay JHZ03-GT-LF AM3 AMD 880G HDMI Micro ATX AMD Motherboard http://www.newegg.com/Product/Product.aspx?Item=N82E168... for only $15 more than the ASUS.

Is that a machine you have or a machine you are building?

You definitely need an upgrade.What is your budget and what do you have on hand as of yet?

well i am visiting family and have the motherboard memory and cpu i did do a makeshift build with using a spare PS they have. I unlocked the other 2 cores and with very little overclocking got it to 3.5 and runs like a champ. I only have stock cooling so dont want to push too hard right now. Also there seems to be a problem sometimes when you unlock that no software can see the temps ive tried them all. Looking at it my video card is my weak point. I used prime95 using 100 cpu and memory and i could still navigate windows really well.
So this is going to be my build, and i got it at a pretty good deal. the motherboard was free with $99 phenom IIx2 560 BE the memory was $49 per stick so i got 2 4 gig sticks so it was about 200. The case PS,harddrive and Video card are off an old system. So i think it worked well