My system configuration:
Core 2 Duo E6750 2.66GHz
4GB Corsair DDR2 XMS2 RAM
1x SATA HDD
1x DVD Burner
20" Asus LCD Monitor
Question: Is this PSU good enough to power my system with the GTX260 in it? I am not going to overclock and wont SLI ever. I am not sure how this ampere thingy works. I understand its a good thing to get a PSU with more wattage than required to keep the system stable on load. How much ampere does this GTX260 require and how do i find out if my PSU can support it? Thanks in advance.
You need a quality PSU which you have picked out. Even the Corsair 550 VX would power your rig. The rule of thumb is a 750W+ PSU is generally only required for Crossfire, dual GPU cards and SLI. Efficiency of a PSU often drops when it is running well below 1/2 rated capacity (not always true nowadays). As the capacitors age in a PSU age the real peak load capacity will start to decline. Also a PSU under or near to full load will have reduced efficiency. Hence why you want to overspec slightly. 600 W is overspec'd for your system so you are fine.
Here is a useful powersupply calculator: http://extreme.outervision.com/psucalculator.jsp
However it rates GPU's at average of maximum 2D/3D load as far as I can make out (the GTX 260 draws more than 119 Watts that the calculator suggests under 3D load).