Would you regret cancelling the cable? Depends on what you like to watch.
If you want sports, Netflix won't cut it.
If you want to watch current season episodes of your favourite shows, Netflix won't have them. However, if you can get Internet on your TV screen, you can often go to the network's web site and watch episodes a few days after they aired. (I know "get Internet on your TV screen" is a dumb way to say this, but my DH is my tech wizard and he was the one who configured the Wii and Playstation to... well, get Internet on our TV screen).
My family got Netflix last year and that's all we watch these days. The selection of movies is good (not great, but good). The selection of old season TV shows is TOO good... my DH and DD are driving me nuts watching whole seasons of How I Met Your Mother, Community, and Breaking Bad in marathon TV viewing sessions.
Why not activate the free trial month of Netflix and try to use only that for a month? If you're happy with what they have, then cancel your cable.