There are some actors (coughOrlando Bloomcough) who repeat the same role over and over again without realizing it. Then there are actors like Paul Giamatti, who's completely aware that his characters are often strikingly similar.

"I suppose I am [typecast] a little bit," muses the New York-born actor, whose latest film, Sideways, hits theaters today. "There's definitely a desperate quality to all of the guys I play. And in the studio films I do, I'm that guy, but a little goofier. I wear a funny hat or get turned blue or something.

"It's weird. I'm either depressed or I'm really aggressive. Some great actor once said that all actors really only have two characters that they play — two basic guys that you play variations on, and that's always what you do. I guess my two guys are Depressed Passive Guy or Psycho Aggressive Guy."

His Sideways character fits neatly into the former category. As Miles, the cynical wine aficionado at the center of the movie, Giamatti wears a perpetual hangdog expression that suggests he's resigned himself to enduring life's hard knocks. In fact, the only time he's happy is when he's uncorking a really good bottle of vino.

Giamatti confesses that he doesn't share Miles' taste in alcoholic beverages. "I know nothing about wine and I don't really care either," he shrugs. "The thing I liked about the character was this persona of the wine expert — this whole idea of wine being something greater that he's aspiring to in life. I studied people who are wine fanatics. A friend of mine is a big wine guy, and he's fascinating because he's a normal human being until he starts talking about wine, and then he turns into a horse's ass."

Although Giamatti has been kicking around Hollywood since the mid-'90s (he first gained attention as Howard Stern's psychotic boss in the film version of Private Parts), he's only recently achieved leading-man status. His acclaimed performance in last year's American Splendor brought him attention — and Oscar buzz — and Sideways seems poised to do the same thing.

"I am getting more interesting lead roles now," Giamatti says. "I said to my agent the other day [that] it would be really nice if I could play somebody who is really calm and in control, like an English butler. But I'm a hard sell, no matter what. It's nice that American Splendor and Sideways make people see me differently, but I think they're actually more confused. They're like, 'Where's the funny hat?'"