I just jumped in on NYC 22 on Sunday nights, about rookie cops on their first assignments. It's pretty good.
Even better is Blue Bloods on Friday nights. It's nearing the end of season 2, so you may have some catching up, but it's really good.
I still watch Criminal Law and Person of Interest as well, which are both tops.
For non-network, catch A Game of Thrones and The Walking Dead, but they both require significant amounts of catch-up to fully realize the stories and relationships.