Lock, Stock and Two Smoking Barrels - Great classic movie, a little bit older but holds well for the time. If you like Guy Ritchie and you did not watch this one, what are you waiting for?? If you don't know who Guy Ritchie is, find out as soon as possible!! I suggest you start with Snatch and then proceed with mentioned movie. You can expect a lot of fun and some action but it requires special taste. Sort of like Tarantino or Del Toro movies. Don't get me wrong, those three film makers have nothing in common except that people either love them or hate them.
Lock Stock is great, but a bit low-budget. Snatch was a huge step up and is one of my favourite films. It's got everything. I've always said it's like a British Pulp Fiction. Shame Guy Ritchie never got close to it again though I haven't seen The Gentlemen yet but I doubt it has anything on his first two.