The third season of Downton Abbey just started airing on PBS in the US. I've already watched the whole thing, thanks to readily-available import DVDs. I'm watching it as it airs regardless, not just because it's really well-done. Knowing what I know about some ENORMOUS twists that were planned from the beginning of the season, I can't emphasize enough that no fan of the program should allow Season 3 to be spoiled for them.
This still from the tail-end of Season 2, where footman/valet/soldier/valet Thomas gets a massive comeuppance and humbling, which he so deserves. As Patton Oswalt put it so eloquently live-tweeting last night's premiere (which combined the first two UK episodes) "even eats oatmeal like an asshole".
As much as I hate Thomas, his development through Season 3 is very interesting. Season 3 is available on Amazon UK , and if you get it, you have to buy the 2012 Christmas Special "Journey to the Highlands" (13.99GBP/~$23 USD), which ends up fundamentally changing the dynamic of the show going forward.