A toss-up between Philosophise This and the BBC's In Our Time for me. Thinking Allowed is also in the mix and I've recently started Mike Duncan's Revolutions which is proving entertaining too.
That one takes few episodes to settle down but all from around ep 40 or so are good. The last few - starting with 179 - are looking at AI and consciousness and covering a lot of great viewpoints.
In Our Time - "Polidori's The Vampyre" and "Thomas Paine's Common Sense" are both ones that I heard recently and found particularly interesting. Also Thinking Allowed's "The Petite Bourgeoisie".