For me two definates are Pulp Fiction and Reservoir Dogs. One summer I has surgery and was pretty much confined to my house, so I watched both of those movies at least once a week for about 3 months. Collateral is another big one, I don't know why, but I watched it 3 times in one day as well as having seen it a half dozen times before. My last two would be Sin City then Kill Bill Vol 1 & 2. I guess in reality I'm just a shameless unoriginal Tarantino fan....or maybe I'm just sick and I like violence...