Maybe this is controversial among TV anglophiles, but I reckon Kevin Spacey's House of Cards improves on the British original, in part simply because of the longer format, which gives the producers more time to create rounded characters. Spacey's lead character lacks the reptilian creepiness of Ian Richardson's original Francis Urquhart (called Underwood in the US series), but also the slight cartoonishness of Urquhart.
So count me in for season 2 of House of Cards, a series that has been aptly described as the anti-West Wing. Not only is the tone much darker than that uplifting depiction of Washington politics, but House of Cards is also the part of the civics lesson that The West Wing left out, the backroom dealing, backstabbing, lobbying and law-breaking that goes on before votes are counted.
(H/t SlashFilm.)