Actually I think that the two you mentioned (Homicide & NYPD Blue) come as close to real life as I have seen. In particular, Homicide's portrayal of some of the small details (such as an endless fleet of identical Chevy Cavaliers for the homicide detectives to use) were exceptionally well done.

In the final analysis none of them come close to real life for a reason. Law enforcement is generally comprised of 99% boredom and 1% sheer terror (American law enforcement officers are not paid for what they do as much as for what they may have to do). Watching a detective wade through a sea of paperwork may be more realistic but it wouldn't make for a very entertaining show .