My philosophy is generally the same as u2slow's. I've bought a lot of parts based on price off Rock Auto, ebay and Amazon and 95%+ of them were good and are still going strong. I've had some cheap sway bar end links fail, an idle sensor go bad and a radiator cap that didn't hold pressure so lessons learned there. When I need something right now I start with Autozone and if they don't have it I go to Oreilly. NAPA is the other parts store in town and a last resort for me - inventory, website and customer service all leave a lot to be desired IMHO. On certain items I'll splurge on good name brand parts (e.g. Moog ball joints) if they're heavier duty than the factory parts and a common failure point. Also, if it's something like a rear main seal or a clutch that would be a nightmare to do over I'll spend a bit more on reputable name brand parts or OEM.
