I thought this would be a pretty cool thread with the new fall season coming up. The one drama I'm definitely going to give a shot is "Blue Bloods", though I don't have high hopes given its Friday slot. "Terriers" looks like it might be worth a shot as well.
My all-time list:
The Shield (unrealistic, but fun)
Rescue Me (a bit more realistic, lotsa fun)
E.R. (first 9 seasons)
24 (first 3 seasons)
Homicide: Life on the Street
Had potential but canceled:
Life (solid writing, acting, plus Sarah Shahi [I][U]and[/U][/I] Christina Hendricks!)
American Gothic (Gary Cole was really good in this)
I definitely intend to add "Dexter" at some point. There really seems to be a dearth of quality dramas on TV, IMHO. I know there are some that I didn't name (Mad Men, Breaking Bad, Sons of Anarchy), but I can't think of many more, especially on regular broadcast TV.