Almost all of my computer science classes had two grading schemes - one "normal" one and another which was basically just taking your grade on the final exam and not counting anything else. That latter option actually saved me one time, but that's because I was astronomically lazy in that class and didn't do anything (didn't even show up to some quizzes, I think, when two quizzes added up to an exam). I definitely think that giving students the option is good, though, because if you asked me which I'd want I will always choose the small incremental tests over one huge test.