I really like to give my business to small family-owned businesses.
Restoration type parts I buy from Hinshaws... met James and the family at Chevell-abration, and the Kansas City Regional. Great people and truly a family operation. Always very honest about the fit & quality of repro parts also.
My suspension stuff usually comes from SC&C (
www.scandc.com) Mark is pretty much a one-man show there... be prepared to spend an hour on the phone with him.
Speed parts, I try to get from a local speed-shop but with their small inventory, it's not often that I couldn't just get it faster from Summit.