Old 20" iMac 2.66ghz vs new 20" iMac

So my girlfriend is about to buy an iMac she was about to buy the 'old' 20" 2.66ghz iMac on Saturday but these updates have come along.

The price has increased in the UK by £20 this is negligible. My question is how do the two compare, the iMac before had a dedicated ATI graphics card with 256MB memory, this has been replaced with the NVIDIA 9400m which is shared graphics. Is this a step backwards?

If the graphics are a small step back do the other improvements make up for this? The DDR3 memory, max 8GB memory is obviously a big bonus. I have read that the new processors used are faster than the older version despite the same clock speed is this correct?

Any help would be much appreciated,

Thanks

After listning to some early podcasts and looking at some benchmarks I do not believe you should regret your purchase at all. The biggest advantage is the DDR3 RAM and its max capacity of 8gb of RAM compared to the 4GB max.

If you are a day to day user I cant see that you would see any difference, enjoy your new Mac.

Any contribution to the thread however is welcome, especially if I have over looked any other components.