iMac New vs Old + graphics

Hey everyone, I am new to the forum and I am thinking about getting an iMac. I do 3d animation, but will only be modeling with this computer in Maya and zbrush.

I am considering the new iMac 20" with upgraded graphics or the old iMac 24" with the 7600 graphics card.

Any thoughts?

I don't have a lot of money so I am looking for something no more than 1500.

The 7600 is faster for some applications, the HD2600 for others.

The faster bus speed of the newer iMacs would make the new model a bit faster for most uses though.

I'd get the new iMac if I were you.