The Shield is entertaining, but to put it in the top 20 of all time is laughable.
Entourage too. Entourage has zero substance. It's entertaining and fun to watch, but it is basically watching a few guys goof around Hollywood with hot girls.
Sopranos is overrated. It's a great show, but not anywhere near legendary.
Deadwood and Rome are probably the best HBO shows outside the Wire. I don't think you could find a single complaint about any aspect of The Wire. I just don't think GOBB has the intellectual capacity to follow a heady show like Deadwood, Rome, etc.