All the major components of your system CPU, Video card, drives, etc. draw from the 12v of which you have 3 x 17a. The video card would require a minimun of 26a of the 12v, which you have. You might feel the unit to see if it is running excessively hot under laod. As long as your not crashing down or running hot, your within your unit's capablity.
I personally question the reliability of that list considering it mentions my ThermalTake 500W purepower PSU as tier 3/4 which to them is rated as bad and to stay away from. Yet it runs my OC E2180/8800GT 4x1GB RAM and all that good stuff just fine. In general though I would say 500W is enough for the system. I believe the specs for my 12V rail's are 12V1: 14A 12V2: 15A
Recommend TP 600>. I think the prior chart makers are referring to more 'extreme' systems with heavy overclocking involved. Plus they are including a bit of power 'allowance' as opposed to everyday PSU situations. Like the computers at my front desks. No need for extremity, but efficiency and reliability are of higher concern.