I loved this show. Only six episodes of The Black Donnellys aired on NBC, but the man and I loved it nonetheless. We just finished watching the rest of the season/series (rented from Netflix). I can't believe it was canceled. It seems that I have a knack for liking shows that not enough of the American populous watches.
The series was written by the writer of Million Dollar Baby and the team of writers behind Crash, both of which won Oscars. As for The Black Donnellys, I either loved the characters, or loved to hate the characters - I think that is key to genuinely connecting with a show.
If you are looking to kill a day, rent the DVDs. You can get the whole series in three discs. Keep in mind that the series ended as if it were going to be picked up for a second season so you may be left wanting more. The man was content with the ending, but I believe that too much is left unresolved. All in all, it is still definitely worth watching.