[quote name='VipFREAK']Yep, that's her. lol, Crazy silly Jane. I really do miss Coupling, but after Jeff left and Susan got pregnant the show wasn't really the same. As for her in Leverage it's not flattering her lets put it that way.[/QUOTE]
Well, the show was always intended to culminate that way. Steven Moffat (the writer) and Sue Vertue (the producer) had recently become parents when Moffat thought how they'd gotten to that point would make for a good show. Originally it was going to almost entirely Steve and Susan but he liked the other actors so much that their roles were expanded and given their own character arcs.
The Jane character in the US attempt at Coupling was one of the major screwups. The actress, Lindsay Price, is way hot but she radiates crazy in a Jennifer Tilly sort of way. This meant anyone encountering her shouldn't be surprised at the things she says or does the way they would when first meeting the Gina Bellman version of the character. Another critical point, Jane Christie (UK) was something of a liar about herself, especially her claims of sexual adventurism. It became plain in the last season that her experience wasn't as varied as she claimed and that she said untrue things, such as claiming bisexuality, to draw attention to herself.
Jane Honda (US) wasn't lying or exaggerating when making such claims. In one episode she apparently slept with both the male and female anchors of the Chicago morning newscast that had her up in the helicopter. This wasn't necessarily a bad thing in of itself but it removed a lot of original character's personality.
Trivia item: In the US Coupling, the actresses playing Jane and Susan both grew up in Arcadia, CA, a little town near Pasadena. I cannot help wondering if they knew each other before being cast on the same show. The eight year age difference means they wouldn't have been in school together.
Anyway, that is one of the things I like about British shows. They're frequently designed with an ending in mind, while US shows are expected to drag on forever so long as the rating are there. US show usually don't have a conclusion unless they've had a long run and the star gives notice that they'd like to stop. The earliest example I know of for this is the original version of 'The Fugitive.'