I've always given a minimum of 2 weeks notice whenever I have left a job, and when I can give more notice I will. At my last job, at a call center, many people gave very little notice whenever they left. I guess that was the culture within that industry, but it still shocked me. One of my co-workers came in one day, and said today was her last day there, so basically she gave no notice at all!
Have you always given 2 weeks notice?