It's the best love story on television. Not Homer and Marge. Not that cute married couple on "Medium." Not the HBO polygamists. It's Denny Crane and Alan Shore in the ABC Tuesday-night hit "Boston Legal," now in its third season, tonight at 9 p.m.

Each episode of the two-year-old dramedy, a spinoff of ABC's "The Practice," ends with lawyers Crane (played by William Shatner) and Shore (James Spader) relaxing on the high-rise balcony of their Boston firm of Crane Poole & Schmidt, recounting their day and their lives thus far.

Sometimes, the two puff cigars. Sometimes, they enjoy a Scotch. Always, they express their love in ways circumspect, tough and touching.

One exchange, in which the characters confessed their many faults to each other, created a signature moment for the pair: Denny: "I'm unfaithful."Alan: "Never to me."

Really, that's all a guy can ask.

Denny Crane and Alan Shore are perhaps the best example of postmodern, heterosexual man-love currently available in the mass media. It has been a long time coming.

"Boston Legal" tells us modern hetero-man can freely love fellow hetero-man without worrying about whether it makes us gay, without spending time thinking and talking about our feelings (gaack!) and without expressing affection solely through physical competition.

Producer David E. Kelley ("The Practice," "Ally McBeal," "Boston Public"), created it as an ensemble. But Shatner and Spader quickly took it over by force of personality. The show has produced solid ratings.

Buoyed by viewer feedback, the writers began to pair up the two in other, off-balcony situations, taking the male-bonding relationship to unexpected places: a fishing trip that included a spooning scene in bed, dressing as matching flamingos at a party, and being tied together with a rope as Denny kept Alan from hurting himself while sleepwalking.

Shatner's Denny is a lawyer-celebrity, a reflexive libertine five times married, a gun-toter (in the office) and quite possibly an Alzheimer's sufferer devoted to making money and the rush of winning cases. Spader's Alan is a hedonist intellectual, self-destructive and self-loathing, willing to hire thugs to rough up a foe and hating himself for doing it. They are both wounded, deeply flawed characters, at once lovable, pitiable and noble.

Yet, like many successful couples, they are opposites in some ways.

Alan has a bleeding heart where Denny is a troglodyte right-winger. Alan lays open his weaknesses while Denny tries to suppress them. And there is a 30-year age gap between the two.

Perhaps it's not surprising that the person who pens most of Shatner and Spader's lines is a woman: Janet Leahy is the executive producer and a writer for "Boston Legal."

"I think of their relationship as (they're) having sex with women, but they're married to each other," she says.

In interviews, Shatner and Spader talk about how the other actor smells, so close is their on-screen contact.

"It's a very funny friendship that Bill and I have and that Denny and Alan have; it really is," Spader says from California. "We go together."