My top 5 list is:

1. WNYC’s Radiolab – the ultimate podcast, Top Gear style production, this is how every podcast should be
2. TEDTalks – nuff said
3. Underreported from WNYC’s Leonard Lopate Show – runs often, wide variety of topics, most are interesting
4. SALT Seminars About Long Term Thinking – great topics, great speakers, from The Long Now Foundation
5. The Economist: The week ahead - to get a headstart on the week, though I’d rather have a Monday edition (this is a Friday edition)

More at Reddit: What podcasts should I be listening to and why?