What are the 20 most important moments in CGI movie history? I take you through my list of candidates. Part #5 of a 5-part series.

4 - The Polar Express (2004)

If you despise motion capture flicks, you should stop reading this section now. Motion capture is the rotoscoping of the new millennium, a bastard sibling that many allege is but a pale imitation of animation. However, motion capture has been used in several prominent movies, including last year's Happy Feet, which won the 2007 Oscar for Best Animated Feature Film.

Based on the bestselling children's book by Chris Van Allsberg, The Polar Express follows a boy who takes an unexpected train ride to the North Pole. Tom Hanks took on at least six voice-acting roles, including the boy who doesn't believe in Christmas, the train conductor, and Santa Claus himself. The story was slight (the original book doesn't have much of a plot either) and many were disturbed by the dead eyes and wax-like skin sported by the film's characters. The Polar Express was a modest hit in 2004, making $176 million in domestic box office.

Despite saying that he doesn't consider motion capture to be an animation technique, director Robert Zemeckis has since produced 2006's Monster House, this year's Beowulf and is making (yet) another version of Charles Dickens' A Christmas Carol for Disney.

Fun Fact: The Polar Express cost $150 million to produce, the same amount that DreamWorks Animation paid for Bee Movie, and Pixar paid for Ratatouille.

3- Sin City (2005)

After movie executives pissed on his scripts for Robocop II and Robocop III, Frank Miller ensured that no one would ever want to take Sin City's stories of vice and mayhem to the silver screen. The graphic novels took 1940's era film noir to the Nth degree, ratcheting up the sex and violence. The resulting concoction went down, to use Harlan Ellison's famous phrase, "like a Drano milkshake."

However, Miller didn't count on Desperado director Robert Rodriguez, who made a short film based on a scene in one of the novels to woo Miller. The short, entitled The Customer is Always Right, became the movie's prologue.

Using plenty of green-screen and CGI, Miller and Rodriguez recreated the world of Sin City, even animating some of Miller's original drawings for key scenes. They used the graphic novels as literal storyboards, resulting in the most faithful translation of a book to movie ever made. Rodriguez even resigned the Director's Guild so that Miller could get a director's credit.

Sin City made $158.7 million worldwide, not bad for a flick that cost $40 million to produce.

Fun Fact: Rodriguez and Miller have already written a script for Sin City 2, basing it on A Dame to Kill For and Booze, Broads and Bullets. However, Rodriguez's involvement with a Barbarella revival, and the box office failure of Grindhouse,may leave Sin City 2 in development hell.

2- 300 (2007)

If Sin City was the warm-up for Frank Miller adaptations, 300 was all Hell breaking loose and inviting Ragnarok along for the ride. Like Rodriguez before him, director Zack Snyder used tons of green screen and CGI to faithfully render Miller's vision of the Battle of Thermopylae onscreen.

However, Snyder's take of heroic Spartans taking on hordes of Persians was more popular with moviegoers. Despite much wailing and gnashing of teeth from the Iranian government (who even protested the film at the United Nations), 300 was the third highest opening for an R-rated film in history. In its debut weekend, the film made back its $65 million studio costs, plus an extra $5 million.

Fun Fact: Many historians chuckled at 300's reference to "Athenian boy lovers," since Sparta was one of the few city-states in Greece to institutionalize pederasty.

1 - Ratatouille (2007)

Ratouille tops this list for one simple reason: it represents the current state of the art in CGI animation. However, Brad Bird's film about a mouse who longs to become a great chef has more than timing on its side.

Walt Disney's animated films arguably represent the pinnacle of cel animation in the 20th Century. Even masters of other animated forms, such as Hayao Miyazaki, recognize the genius in movies like Snow White and the Seven Dwarves, Fantasia, Sleeping Beauty and 101 Dalmations.

Ratatouille is the first CGI animated film to be directly compared with Disney's greatest work. On IMDb's Top Rated Animation Titles list, Ratatouille takes the #2 spot with an 8.3 out of 10, just below Miyazaki's Spirited Away.

I've used Vic Taboush's quote about Ratatouille ("(It's) the best animated film since Pinocchio") a lot, but it bears repeating. Taboush, who worked on 1950's Disney films like Lady and the Tramp and Sleeping Beauty, puts Ratatouille above every movie he ever worked on. That gives you some idea of this film's achievement.

Whether or not Pixar can repeat this feat remains to be seen, but future students of animated film will be studying Ratatouille very carefully.

Fun Fact: Neither Peter Sohn (who voiced Emile) and Lou Romano (Linguini) are professional voice actors, but they're Pixar animators who did rough drafts of various scenes using their voices as placeholders. However, Bird liked their performances so much that they voiced the characters in the final movie.