Secret Agent (A.K.A. Danger Man) Complete Series
Ah, Danger Man. This set is up on Amazon for a measely $99 bucks right now. It's everything including both the original B+W half hour show, and then the color ones that were on CBS back in the day. This is first part of the Prisoner. Really, it is. If you like the Prisoner, you'll like this. It's much less weird, but very much in the same world, and really the set up for what happens there.
John Drake is Number 6 and vice versa.
In any event, I don't know that there's ever been a better spy show on TV, and that includes 24. Go, watch.