People who don't know any better regularly suggest a PSU four times the size actually needed. Also having 3+ hard drives or "tons of RAM" has very little impact on PSU requirements. HDDs use around 20 watts during spinup then settle down to (generally) less than 10. RAM varies, but expect under 10w per 2GB.
I ran an overclocked 9800GX2 with an E6750, 3 HDDs, 4 sticks of RAM, and 5 fans... On a cheapo Antec 450w PSU.