I work in a field that requires us to give a month's notice. I've found that if you're leaving a workplace, higher ups take it personally at times, or just want to cut off loose ends. There's absolutely no point to giving even two-weeks notice. These workplaces won't give you five minutes notice upon firing you, and they absolutely don't need your courtesy of training new employees to do your job or tying up loose ends for them before leaving. They can figure it out, after all workplaces have infinitely more power than individual workers do. I've adopted a policy of leaving the same day I hand in my resignation and human resources departments can't say anything more than hire and end dates. If they do, or if a new employer calls an old employer that is not on your reference list for an opinion on you, you wouldn't want to work for them either. That's a red flag of an unethical, unscrupulous workplace.
Polish up your references, leave the same day. If you stay longer, you're a threat because you have important information, you're deadweight that likely won't put in the same effort, and you'll probably make others jealous. Keep it all quiet, hand in your resignation and don't let the “leaving without two weeks notice is bad professional conduct” threat bother you. We're not in the 1950's anymore with any semblance of employer-employee loyalty.