Although the incomparable character actor William H. Macy is versatile enough to be as brilliant playing a fast-talking race track announcer in "Seabiscuit" as he is playing an ego-inflated ratings expert on the short-lived sitcom "Sports Night" or a goofball superhero in "Mystery Men," he's best known for bringing depth and bittersweet irony to sad sacks and milksops.

With his roles in "Fargo," "Boogie Nights," "Magnolia" and "Panic," among other films, Macy has always made a lasting impression, but the actor has recently said he's done with good-hearted losers, and if that's the case, he's sure going out on a virtuoso high note with "The Cooler."

Yes, nobody plays a rube as well as William H. Macy, and Bernie Lootz is a rube of epic proportions -- a guy with such an aura of ill fortune that he makes his living at a declining Las Vegas casino, bringing bad luck to hot-streak gamblers. The film's amusing and energizing opening is a tracking shot that follows Bernie simply walking through a forest of slot machines and a cluster of craps, cards and roulette tables as everybody in his wake -- everybody -- starts losing, and losing big.

For the last five years, Bernie's been doing this as way to pay off a huge tab he ran up on his own losing streak that ended when the casino boss -- Bernie's callous old pal and Coney Island short-con partner Shelly Kaplow (Alec Baldwin) -- capped his knees. "I got off easy," Bernie smiles meekly when telling a haggard but pretty new cocktail waitress named Natalie (Maria Bello) how he wound up exuding bad hoodoo for a living.

But in six days, Bernie's debt will finally be paid, and there's nothing that could keep him in Vegas after that -- except perhaps a haggard but pretty cocktail waitress, who seems vulnerably drawn to his poignantly self-deprecating pessimism, even though he can't even outlast his old record of "Luck Be a Lady Tonight" when she takes him to bed.

Written with astute affection and directed with stylish vim by newcomer Wayne Kramer, "The Cooler" turns on the fact that falling in love changes Bernie's luck -- and that's bad for business. It's especially bad for Shelly, a Brooklyn mook whose only life for 16 years has been running the casino and who refuses to recognize its decline. He's old-school Vegas, but the mob types who own the joint have gone corporate and want to Disneyize like the rest of The Strip -- which just makes Shelly sick to his stomach (as evidenced by one of Kramer's creative transitions, in which a poker chip flipped into the air becomes a tab of Alka-Seltzer falling into a glass of water).

Baldwin does his best dramatic work in years as the broken-down but brusque and intimidating casino boss who was already trying to undermine Bernie's departure plans before Natalie came along. So Bernie's newfound spring in his limping step really chaps the guy's hide.

Bello ("Auto Focus," "Coyote Ugly") is memorable too, tapping into the wounded soul behind Natalie's strenuous optimism. Shawn Hatosy ("Outside Providence") and Estella Warren ("Planet of the Apes") are spot-on as Bernie's estranged son and his pregnant girlfriend, low-class swindlers who blow into town looking to score some guilty-father money and getting more than they bargained for.

But Macy's ability to turn out another agreeable, pitiable schmuck of a completely different stripe than any he's played before is what really gives "The Cooler" its heart.

The film suffers ever so slightly from one obvious plot twist and a completely unnecessary parting-shot line of dialogue that breaks the movie's spell just as it's ending. But if this really is Macy's farewell to rube roles, it's a winning epitaph.