I don't understand the people with job experiences of getting let go the same day they put in their two weeks... how unimportant are you to your company where they are confident that you can drop off the face of the earth and the whole ship will keep humming along?
I know with people in similar roles to my own, we frequently ask for the 1 month notice to help with the transition. But I think that just comes with the game with a technical role, it takes a while to get someone up to speed. I've even see what Mrs. Gooch suggested play out, where a guy put in his 2 weeks mid project and they got him to stay on as a higher paid consultant for a few months after. My warning on that would be, if you ever wanted to work there/with those people again, that action can kind of leave a sour taste in the mouth.