Finchley central is on the High Barnet branch of the Northern Line (the black line)
Finchley Central is not the nearest tube station to my home but it is the easiest to get to - just hop on a bus and it takes less than 6 minutes except if there is an accident on the North Circular and then it can take almost 40 minutes. The trick is knowing if there is an accident before you board the bus - then its a good 20 minute walk or an 8 minute run.
I exited Finchley Central on Sunday evening because I was coming home. One of the things I like about Finchley Central station is that The New Vaudeville Band once had a hit single about it.