First, there is a difference between what the OP wrote, and what everyone read. The OP said "i have a coolmax 500w psu", and everyone replied about the "I have a coolermaster 550W" Can you see the error now?
Second, I would agree with the xtremesystems list. Coolmax isn't known for producing the best PSU. I would certainly want to buy one that "would still probably last you a good year."
Third, while I understand he "drew first blood", Masterjaw didn't "overestimate power requirements". He didn't say to run a 750W PSU, or anything larger. For whatever reason you believe that PSU is ok, but most of us here would not. That company isn't well known, and is on a good list as a tier 5 PSU. I would avoid it for those reasons alone. (Coolmax does have some psu that are rated higher, but they are 750W and above.)