As for Spaced I think Simon Pegg said it best when he said 'Spaced is just us messing about from the idea "2 people share a flat", the US can take that idea if they like, but please don't call it Spaced'
(Completely bastardised version of a quote I cba to look up)
For me tho, the Office is one of those US shows that has broken free of its UK parent and made its own path, and has earned its right to exist.
Shows like Coupling US, I just cannot see the point of tho. The whole point of Coupling, was you take friends, and put some funny stuff and jokes in where the saccharin was. Also, it was about how the British tend to deal with relationships, as in so many cases, moving it to America kills half the jokes.
Also, one advantage the brits have, we're willing to hire people who look funny to be in comedies, you can have funny teeth or big ears or hilarious hair, and still get on TV. It's hard to carry a show that's about your failure to get women when you look like you fell out of fashion magazine.
On a side note from Office tho, if you haven't done it, seek out some mp3's of 'The Ricky Gervais Show' even if you hate him. Karl Pilkington is one of the comedy finds of the decade, imo. He is truly this millenium's court jester and village idiot, he's the village idiot of Britain.
A few quotes of his from the chats on the show.
When asked about dopplegangers - "How would I know which one I was?"
When asked about global warming- "They keep saying that sea levels are rising an all this. It's nowt to do with the icebergs melting, it's because there's too many fish in it. Get rid of some of the fish and the water will drop. Simple. Basic science."
On Rome - "I think it's clever how Rome have kept a load of old stuff. There's no overheads, yet people are going over there to see it."
I admit a lot of it is his delivery, and I'm not quite convinced its an act, if it is, he's a comedy genius, if it's really him, he's a whole new kind of genius, the sheer volume and type of idiocy that tumbles out of his face.