Doo it

Here's a no-brainer: Scooby-Doo, why are you?
You've got your GenXers with happy memories of the 1969-72 TV series and its spinoffs, and some of them have children of their own they want to expose to it. Theoretically this dual demographic will keep theaters packed for both matinee and evening shows.
What they'll see is loud, campy, and colorful. The movie most nearly comparable is Casper, but Scooby-Doo is aimed at slightly older kids and slightly younger adults. There's even a ghost in the opening scene, which like a James Bond film throws us into the climax of a previous adventure, The Case of the Luna Ghost.
The Mystery Inc. gang saves the day, rescuing Daphne (Sarah Michelle Gellar) and, thanks to Velma's (Linda Cardellini) brains, solving the case. Then they go their separate ways. "I'm so over this damsel-in-distress nonsense," Daphne complains. Fred (Freddie Prinze Jr.) and Velma are also tired of their roles; so they drop out, leaving only Shaggy (Matthew Lillard), "the dude who carries the bags," and of course Scooby-Doo.
The animated dog suffers from being partnered with Lillard, who is more animated than anything a computer can yet create; but they make a cute couple ("You drink out of a toilet," Shaggy reminds his friend and Scooby responds, "So do you") and there's good attention to detail: when Scooby-Doo licks Shaggy's face you can see the saliva glistening on his cheek. Er, maybe that's too much attention to detail.
Two years later the gang is reunited when they each receive invitations to Spooky Island, "the frighteningly popular spring break spot for college students," run by Emile Mondavarius (Rowan Atkinson). It seems visitors to this theme park are being turned into Stepford students. (For a more serious treatment of the same idea see Disturbing Behavior.) As our heroes explore the Haunted Castle in search of clues it's like the Thir13en Ghosts remake with a plot.
The island, of course, has been turned into a "brainwashing facility for an evil cult"; and the future of the world, at least for the next 10,000 years, hangs in the balance. Who's behind the plot will come as a surprise. A climactic body-switching sequence is funny, if overextended, but for many viewers the comic highlight will be a farting and belching contest between Shaggy and Scooby-Doo. The final confrontation involves more effects than wit, but that's becoming Warners' trademark after Queen of the Damned.
Prinze may have found his niche doing intentionally bad acting– the unintentionally bad acting wasn't working for him– and he looks cute as a bleached blond. Gellar, his fiancĂ©e at last report, could lighten up a bit more but isn't bad. This is a comedown for Cardellini after Freaks and Geeks, but it should raise her profile and lead to better things. Lillard is in a class by himself and may wind up in a movie by himself when he runs out of co-stars, human and animated, willing to be upstaged by him. In their Scooby do's he and Prinze could segue into a remake of The Many Loves of Dobie Gillis.
"Fred thinks I should have learned French," Shaggy says, "but I say you don't have to know what 'Voulez-vous coucher avec moi?' means to love that song!"
The other Shaggy contributes a song to the mostly hip hop lite soundtrack. So does Sugar Ray, but they appear in the film to sing it, with Mark McGrath flirting with Daphne from the bandstand. Also putting in cameo appearances are Pamela Anderson and Scrappy-Doo. Of the latter Velma reports, "He wasn't even a puppy. He had a gland disorder."
I can't say I'm looking forward to the seemingly inevitable sequel but Scooby-Doo avoids inclusion on the American Film Institute's list of "100 TV Series that Shouldn't Have Been Turned into Feature Films." (No, not yet, but they'll get around to it.)