Supposedly despite the locked multiplier the 95W version of the Phenom II X6 1055T is meant to be quite decent for overclocking and may need less voltage too. However,the unlocked multiplier of the Phenom II 1075Twill make it easier to overclock. However,the 890GX based motherboard I listed is supposed to be decent for overclocking though.
I do agree with scaryjim aout getting 2X4GB even if it is slightly more expensive as it means you could have up to 16GB of RAM.
If you need more video RAM perhaps you should look at the GTX480:
http://www.ebuyer.com/product/202257
This uses the GF100 GPU.
There is also the GTX580:
http://www.ebuyer.com/product/246903
This uses the GF110 GPU. It has more shaders and high clockspeeds than a GTX480 and reduced power consumption.
It looks like the GTX580 should be faster than GTX480 in GPGPU tasks:
http://www.anandtech.com/show/4008/n...orce-gtx-580/2
However,it seems that there maybe issues with 3DS Max with the GTX400 series GPUs:
http://en.wikipedia.org/wiki/GeForce_400_Series
I would read the links in the article.
TBH,it maybe also worth looking at a Quadro card as these have more video RAM.
The Quadro 4000 has 2GB of video RAM but only 256 stream processors and costs around £700 to £800.