It depends upon the movie. If it is a movie that is not too old but I want to see right away Red box is what I love! Pick it up tonight and return it tomorrow.
If it is a movie for my kids that I know they will watch 100 times I prefer to buy it.
If it is a bit of an older movie that I have wanted to see for a while or a movie that my kids want but I do not think they will watch it more than 2 times a year then I love Netflix. I also love Netflix for their play instantly menu especially since now we can use our wii to watch them on our tv rather than tying up the computer.
Sorry to say but Block buster just does not make the list for me since I am way too much of a cheapskate!