Econtalk is hosted by Russ Roberts, a Hayekian economist. Episodes are weekly and an hour long. I've enjoyed many of them.
FORA.tv is full of talks by the authors of the 'important book of the month', and the talks tend to be an hour long.
London School of Economics has two podcasts I think. One I like, one I don't like. The one I like is actually economics professors giving talks about their research field to other LSE members. It's much more boring, but I like it quite a bit, since I like listening to professors talk within their fields.
The Royal Society for the Arts is like Fora.tv, but slightly worse audio
Quirks & Quarks is one hour per week, and is science discussion for the layman. It does some of the 'science stories of the week', but also longer interviews in different fields.
Both top-tier science journal Science and Nature have their own weekly podcasts. They're a bit less for the layman. I highly recommend them, but only if you're fond of science.
edit: for most lecturers/intellectual speakers, I'd recommend using the 2x setting for your playspeed. A lot of speakers enunciate, and this enunciation allows us to listen to them at faster rates.