|the extended version is designed primarily for 3d graphics, special effects and illustration...for graphic designers basically.|
if all you use PS for is editing photos, then the standard cs4 is more than enough program for your money.
i have the extended version and havent touched about 50% of its features
Vista nVidia Evolution SP2
Intel(R) Core(TM)2 Duo CPU E6550 @ 2.8GHz
XFX GeForce 9800 GTx
4GB OCZ Platinum 1066
2x Samsung 1TB Spinpoint F1