Following on from the French film thread in Other Stuff (which is where this one'll probably end up, sorry mods), I thought a similar thread of US television series would be useful.
Mainstream stuff doesn't count (24, West Wing etc), but if it was only shown late night on BBC2, Sky, Ch4 or Ch5 please include it. Equally, if it's never been shown over here but you've seen it and recommend it heartily, post it here.
On my computer I have Treme (from The Wire lot) about the New Orleans floods, Breaking Bad, a dark dark comedy(?), and Weeds, no idea but someone told me to watch it, ready to go. Oh, and Blue Bloods, from NSC.
I recommend Alias, light spy caper but great fun, The Shield, brilliantly involving cop drama, and, criminally cancelled by FX after just one series, Terriers, about a couple of middle-aged private eyes, which if you can get a look at it is superb.