Quality of mail order vs retail components

I built a system a year ago. P4 Northwood, ASUS P4C-800E Deluxe, Patriot ram 4x512, WD Raptor 74, OCZ PS. I assembled it carefully guarding against static, etc. I had one stick of ram fail memtest (fixed with voltage adjustment), Raptor died one month ago, now mobo dead probably. Everything is on a higher capacity APS surge protector, the environment is not hot and I power on and off 1-3 times/day. Mobo and Raptor from ZZF, rest from Newegg.

I was picking up a laptop at a local repair shop and the proprietor said that parts from mail order vendors are lesser quality than from retailers buying from authorized distributors. Given the problems with my first build, I'm wondering if he's got a point, if I made mistakes while building or am just having bad luck. I've had several computers from Gateway, one from ABS, one from Micro Express. I've had a few hard drive failures and a Gateway laptop mobo failed after about 3 years.

Any thoughts?

David