These might not be the best movies in the specific genres but they work great for movie marathons, especially since no one movie stands out against the rest by a huge margin. You don't want to see one amazing movie and then keep comparing four average movies to it. You want to equally enjoy all the movies. Also the above are the movies that I've seen and have DVDs of. There are so many other movie-marathons I can add to the list and I probably will later. But that's it for now.
I don't know what my next movie marathon would be but I can't wait. I already got the popcorn, chips & salsa, Red Bull, and Coke Zero :) Who's up for it?