Yes, it will be fine. Your card only pulls 140 watts.
http://www.geforce.com/hardware/desktop-gpus/geforce-9800-gtx/specifications
The recommended PSU wattage is 450 watts. You will be fine with 500 watts.
If you plan to run SLI you will need a bigger PSU though.
You can use this calculator to get an estimate of how big of a PSU you need.
http://extreme.outervision.com/psucalculatorlite.jsp
I would NOT recommend Cougar for a PSU brand.
Get a good brand like Seasonic, Corsair, and XFX.
The Seasonic and XFX are much better then the Corsair (CX) if you have the money.
That courgar PSU does not even put out the minimum recommended wattage though.
It can only put out 430 watts. Recommended is 450 watts.
Get something like this...