Breaking up is hard to do, as the song says, but that's hardly a newsflash for anyone who has endured the singular agony of being kicked to the proverbial curb. Untold millions of books, movies and songs have commemorated the hell of being dumped -- the tears, the depression, the subsequent boozing, the rebound, the stalking. With that much heartache, it only stands to reason that breakups have all the makings of first-rate comedy.

At least that's the thinking of Jason Segel - and we're thankful for it. As the screenwriter and star of Forgetting Sarah Marshall, this alumnus of the Judd Apatow School of Comedy uncovers comic genius tucked inside the misery of romantic rejection.

He also uncovers plenty of good raunchy fun. In keeping with such Apatow films as Superbad, Knocked Up and The 40 Year OId Virgin, Segel and director Nicholas Stoller fashion a hard-R comedy. In fact, that gauntlet is whipped out -- er, thrown -- in the opening minutes, when Segel figuratively and literally gives meaning to the concept of "naked vulnerability."

As Peter Bretter, Segel (an Apatow regular dating back to the late, great Freaks & Geeks television series) plays a sad-sack composer who scores the musical cues for a cliché-ridden TV cops series. He's a confirmed couch potato, the kind of schlubby guy who wears the same sweatpants for a week and slurps his cereal from big mixing bowls, but he also has the good fortune of being the longtime boyfriend of the blonde and beautiful Sarah Marshall (Kristen Bell), the TV show's leading lady.

Alas, Sarah breaks up with Peter in one of the all-time great -- and cringe-inducing -- breakup scenes in the history of cinema. Peter eventually tries to rebound through a series of very funny one-night-stands; "I need to B my L on somebody's Ts," he discreetly explains to his stepbrother, Brian (the dependably hilarious Bill Hader from Saturday Night Live). But casual sex doesn't reduce Peter's crying jags -- not even when he's in the middle of "things" -- and so he jets off to clear his head in Hawaii.

But Peter, who makes the mistake of checking into a resort that Sarah had once talked about, quickly discovers that his ex is also a guest at the hotel. She's not alone. Sarah is with her new squeeze, a mega-libidinous British rock star named Aldous Snow (Russell Brand). Peter suffers through a host of painful -- and painfully funny -- situations, determined not to be run off. It helps, of course, that he is befriended by Rachel Jansen, an amiable hotel hostess played by the stunning Mila Kunis (of That '70s Show fame).

The picture's blend of deliriously smutty humor and genuine warmth will be familiar to anyone who knows the Apatow blueprint. By all rights, the hybrid shouldn't work as well as it does, but Forgetting Sarah Marshall strikes a beautiful balance between riotous laughs and authentic emotion. First-time director Stoller, who was a writer on Apatow's short-lived Undeclared TV series, weaves an agreeably breezy, laidback pace. As for the script, Segel's comic sensibility might be driven by his penis, but the characters he creates are all heart.

The filmmakers benefit from a wonderful ensemble cast. Segel does a nice job as the lovably sensitive man-boy, while the off-the-charts sexy Kunis commands the movie every time she turns up on screen. As the endearingly cocky Aldous Snow, Brand displays strong charisma and impeccable timing. Bell, despite being the titular character, is the weakest of the leads, but she does manage to add shadings of vulnerability to what easily could have devolved into a one-note role. Rounding out the cast are dependable Apatow regulars such as Paul Rudd as a zonked-out surfing instructor, Jack McBrayer as a sexually naïve honeymooner and an absurdly miscast Jonah Hill as a sexually ambiguous celebrity stalker.

This two-disc "collector's edition" includes both the theatrical and unrated versions. The difference is about six minutes, most of it being in the form of an added scene in which Peter, Aldous and Sarah take a yoga class from a sexually charged instructor played by SNL's Kristen Wiig. The vignette is a keeper. Less successful is the inclusion of a brief scene of Peter on the flight to Hawaii.

Horny male viewers might also want to make note that the unrated version does add a topless woman in the montage of Peter's ill-fated one-night-stands.

The two-disc edition is housed in a plastic keepcase with a swinging tray. A heavy paper slipcase boasts the same cover art as the keepcase.

Presented in anamorphic widescreen 1.85:1, picture quality is very good. Despite some minimal grain here and there, particularly in nighttime scenes, the images are clear and crisp, with solid details and vivid colors.

The Dolby Digital 5.1 audio is strong and clear, but the rear speakers only seem to get a workout when it comes to the scenes of Peter's attempts at surfing. Audio tracks in Spanish and French are also available in 5.1. Optional subtitles are in Spanish, French and English for the hearing-impaired.

The bonus features on Disc Two have a 2.0 mix, with optional subtitles in Spanish, French and English for the hearing-impaired.

The bulk of special feature are on Disc One. Kicking things off is a fun, spirited and occasionally meandering commentary featuring director Nick Stoller, executive producer Rodney Rothman, producer Shauna Robertson, Jason Segel, Mila Kunis, Kristen Bell, Russell Brand and Jack McBrayer.

Six deleted/extended scenes can be viewed separately or via a "play all" function. They're worth a look, but were excised for good reason. Of particular interest is an airport farewell between Peter and Sarah. The footage has an aggregate running time of eight minutes, 34 seconds.

Line-o-Rama (7:49) collects a bunch of discarded, improvised lines, many of which are pretty damned funny. A five-minute, 44-second gag reel includes the expected guffawing. More entertaining is raw footage (7:14) with lots of flubs and giggles during the shoot of a video-chat scene involving Segel, Hader and Liz Cackowski.

"Dracula's Lament" table read (3:17) captures Segel's first performance of the rock opera penned by his movie alter ego, Peter Bretter. "A Taste for Love" (6:18) details the all-puppet Dracula musical that Peter yearns to make. Fans will love it.

"We've Got to Do Something" (3:48) is the full version of the music video that Russell Brand, as Aldous Snow, performs in the film's beginning moments. Rounding things out on Disc One is the red band trailer.

Disc Two is an embarrassment of supplemental richness. I can't imagine that anyleftover footage has not been saved from the cutting-room floor.

Perhaps the most substantive extras are 21 video diaries of behind-the-scenes footage. The tone is relaxed and funny, with Segel and Stoller doing a good job as our hosts. Aggregate running time is just shy of 35 minutes.

Five more deleted/extended scenes have an aggregate running time of 10 minutes, 56 seconds. Viewers can check out each one separately or play all consecutively.

"Dracula's Lament" mixed version (2:18) is Jason Segel goofing on his rock-opera number, performing it alternately as Tom Waits and the B-52's Fred Schneider. A two-minute, 30-second puppet breakup is a wisely scrapped puppet recreation of the Sarah-Peter split. Moderately entertaining is edited footage spliced together as Sex-o-Rama (2:44) and Drunk-o-Rama (2:31).

Russell Brand: Aldous Snow is a five-minute, 56-second featurette about how the British comic brought a rethinking of the character. Segel had envisioned Aldous as an erudite literary figure, but Brand's rock-star charisma prompted a rewrite. The actor's wit is on display in the mock children's TV program, The Letter "U" with Aldous Snow (3:47). And in case all that isn't enough for you, check out the nine-minute, nine-second raw footage of Aldous and Peter talking in the hotel lobby.

Another section of extras is dedicated to Sarah's ersatz TV series, Crime Scene, including alternate scenes (2:21) that didn't make the final cut and a Hunter Rush Line-o-Rama, which is nearly two minutes of self-consciously hardboiled dialogue courtesy a very funny Billy Baldwin. Sarah's New Show: Alts (2:15) rounds up some also-rans not used in the theatrical version.

Viewers can also check out videotaped auditions of Kunis, Bell, Brand, McBrayer and Maria Thayer, who plays McBrayer's new bride. Total running time is 15 minutes, 32 seconds, although each audition can be viewed as a standalone.

Last but not least is an 18-minute, 38-second promotional piece, Cinemax: The Final Cut.

Oh, and just in case you're a total ingrate and the aforementioned bonuses aren't enough, the package tosses in a digital copy disc.

It's not as uproarious as Superbad and perhaps not as emotionally resonant as The 40 Year Old Virgin, but Forgetting Sarah Marshall finds an irresistible balance between hard-R comedy and sweet-natured romance. The movie might be most notorious for Jason Segel literally letting it all hang out, but his considerable heart is what makes Forgetting Sarah Marshall so unforgettable.