This is one of the most visually stunning and thematically moving epics in recent memory, and in spite of numerous minor flaws, Scorsese's best in more than a decade.

Gangs clocks in at a little under three hours, and Scorsese clearly had enough material for three more. This is the rare film that's too long and too short at the same time - too long because three hours is long for any movie, yet too short because clearly much important material was cut out in order to get the film down to a more manageable running time. The movie arrives a year later than originally scheduled, as Sept. 11 and reported struggles on the set between Scorsese and Miramax boss Harvey Weinstein.

Leonardo DiCaprio (all grown up, and showing considerably more gravitas than in his Titanic days) stars as Amsterdam, a young Irishman who as a young boy watched his father (Liam Neeson) be killed in a gang battle by powerful, blood-thirsty gangster Bill Cutting (Daniel Day-Lewis, in a career performance). Fifteen years later, Amsterdam returns to the Five Points with revenge on his mind, and in the meantime falls for a comely pickpocket (Cameron Diaz).

This is a great cast, all at the top of their game, but nothing will prepare you for how great Daniel Day-Lewis is in this role - that rare period villain with a New York accent. It's a showy role, and while Day-Lewis dominates every second that he's on screen, he's always believable.

Diaz as Jenny is more or less shunted to the side after being established as threatening tough-girl in the film's first hour for a girlfriend role, in what's probably the film's biggest weakness. There's also a hint of a love-triangle subplot involving Amsterdam's friend (E.T.'s Henry Thomas) but that apparently ended up on the cutting room floor as well.

One of the most enjoyable aspects of Scorsese's best recent pictures (Goodfellas, Casino, and the underrated Bringing Out the Dead) have been those moments of exposition, which explain "how things work" in the world of the film. Gangs is no exception, as Scorsese does a masterful job of explaining who's who and what's what in the Five Points of 1864. There's a lot of colour in this film, and Scorsese makes the most of it.

Gangs is full of great visuals, most notably the early shot of a door opening into a snow-covered Five Points. There's also a great 45-second steadicam shot depicting Irish immigrants getting off the boat, signing in, enlisting in the Army, and immediately boarding another boat, to ship out.

The film ends with a stirring re-enactment of the 1864 Civil War draft riots, juxtaposed with the final confrontation between Amsterdam and Bill. From the beginning it's a bloody picture, but the finale sequence literally features pools of blood in the streets - bloodier than anything in Saving Private Ryan. It's on a grander scale than anything previously attempted by Scorsese, and he does an excellent job with all of it.

Great as it is, Gangs is only the year's second-best period drama about Irish-American gangsters, after Road to Perdition. Like Sam Mendes in that picture, Scorsese loads the film with Catholic imagery, and places special emphasis on fathers and sons. And Scorsese loses nothing in the translation to Irish gangsters- in Gangs, there's not an Italian in sight.