BECKETT AND CASTLE

The two heroes of Castle started their crime-fighting partnership in the time-honoured tradition of winding each other up like no one's business. Indeed, cocky crime author Richard Castle wasted no time with the wisecracks when he found himself teamed up with cop (and begrudging fan) Kate Beckett, and before long she succumbed to his unstoppable schoolboy charm. Of course, it helps that Castle and Beckett rapidly made one heck of a team. And let's not forget the fact that, despite being a hard as nails detective, Kate is just as creatively minded as Richard - to the point where they can banter about comic strip superheroes and sci-fi shows. Little wonder they ended up becoming more than just professional partners. Fans across the world couldn't help but sigh and swoon when this double-act made things official.

RIZZOLI AND ISLES

One's a blue collar butt-kicker, the other's a fragrant fashionista. On paper, Jane Rizzoli and Maura Isles really have no business getting on with each other as well as they do. And yet... they bring new meaning to that silly phrase "BFFs", balancing each other out perfectly. Rizzoli is fierce and fiery, hailing from a blunt Boston background where people say it like it is and believe in hard graft. The fact she's literally scarred from her confrontations with vicious killers just adds to her tough façade. Yet her secret softness is brought out by Maura, a forensics expert who looks like she's stepped out of a glossy magazine. If Rizzoli is "dark" and gritty, then Isles is sweetness and light, but add one to the other and you have a powerhouse pairing to strike fear into the hearts of cunning killers everywhere...

ROSEWOOD AND VILLA

You know what they say about oil and water? Now think that, only more so. That sums up the relationship between Dr Beaumont Rosewood and detective Annalise Villa. Consider the fact that he's a breezy, dynamic, quick-quipping charmer who treats life like one big fairground ride, while she's a serious, no-nonsense cop fond of belting bad guys' in the nose. Not exactly on the same wavelength, especially when you consider the private trauma that's brought Annalise back to Miami - and into Rosewood's orbit. Still, he's not the kind of guy who backs out from a challenge, and thinks his skills as a forensics investigator will win her slow respect. Of course, the only way he'll know if he's broken down the barriers is if she deigns to call him by his preferred nickname, "Rosie".

HOLMES AND WATSON

Sherlock: "Punch me in the face. Didn't you hear me?"
Watson: "I always hear 'punch me in the face' when you're speaking but it's usually subtext."

That exchange between Sherlock Holmes and Dr Watson rather nicely sums up the dynamic of the two men: pompous entitlement from Sherlock, exasperated impatience from Watson. Yet there's so much of a connection between the two that they can fight (in this case, very literally) without ever losing sight of the fact they have a bond so deep, it can survive the interference of lunatic killers, cunning baddies, and Sherlock's innate ability to make Watson want to chew his own face off in annoyance. Never mind crime-fighting duos, these two might be the best TV duo, full-stop. (Even if they'd never, ever admit it.)