I didn't plan it by I just saw two movies with Sienna Miller, Interview and Factory Girl. Both movies explore how a messed up, druggy famous beauty deals with her fame. Factory Girl is about Edie Sedwick, an Andy Warhol groupie in the 60s who dies too young. Interview is a strange little film with Steve Buscemi who stars and directs with Sienna Miller. The whole movie is basically those two talking; he is a political reporter slummin' it by interviewing a B-movie actress. It's based on a Danish movie and really just kind of strange. One thing for sure is that Sienna Miller is lovely and magnetic, but both movies are just kinda so-so.
Oh and I also saw Eastern Promises with the studly Viggo Mortenson as a tatooed Russian mafia thug. Pretty violent and not as good as The History of Violence by the same director, but you do get see Vigo all nude and stuff in a steam room hopping around killing people. So if you're into that.