For most people, the standard (and bare minimum) is two weeks. If you really liked your job but just found a better opportunity, then do everything possible to give them as much time to mitigate your loss as possible. This shows your appreciation for everything you've learned while on the job, and maintains a positive relationship going forward. But even if you had a terrible boss at a rotten company, you should still give them the courtesy of two weeks notice because you're a professional.
Some businesses might be choose to escort you out the door early. That's their call. But you should still stick with the courtesy of giving proper notice.