Podcasts have a narcotic appeal to me. The moment I start my car, have trouble sleeping or walk any distance longer than fifty metres, out comes the iPod, and on goes my podcast de jour. Here's my current list of the best and brightest of that cohort:

Sound Opinions from American Public Media: a diverse survey of rock and roll in all its splintered glory, featuring album dissections, interviews, reviews and a caustic view of the commercial pop industry.
Archaeology Channel: An earnest round-up of things excavated and interpreted, from the glories of the classical world to lesser known civilisations.
Reason TV: Provocative asides from the libertarian fringe, hacking away at the jungle of big government.
Science and the City: Despatches from the New York Academy of Sciences, covering public lectures by prominent scientists, the intersection of art and science and on location with interesting research projects.
Are We Alone -- Science for Thinking Species: A slightly whimsical survey of science, skepticism and astronomy, leavened by bad puns, two excellent presenters and a roll call of the world's best scientists.
Design Tools Weekly: An advertorial laden, but still useful listing of recent software releases for design mavens.
InDesign Secrets: one hundred episodes on one program, and the well is not yet dry. The hosts are enthusiastic and committed to their subject.
Mac OS Ken: Mac News from a sardonic and well-informed commenter, retailing tenuous gossip and better founded analysis.
Mark Kermode and Simon Mayo: frequent and entertaining rants on matters cinematic from Dr Kermode, with droll asides from the show's presenter.
Material World: Science interfacing with engineering, a presenter with a taste for alliteration and wordplay and researchers fresh from the cutting edge.
Media Watch: Web edition of an acerbic TV program dedicated to shining a light on the lower life forms of the media world
New Yorker -- Out Loud: Featuring a discussion of an article in the current edition of the New Yorker, low key in that inimitable New Yorker way.
New Yorker -- Short Stories: A prominent writer reads their favourite short story from the New Yorker, then discusses it with the show's presenter.
Philosopher's Zone: Exploring all parts of the philosophical realm, the presenter a congenial and knowledgeable companion.
Planetary Radio: fairly high-keyed look at space exploration from a space-activist point of view, with (literally) stellar guests.
Slate's Audio Book Club: unashamedly elitist autopsy of a classic or recently published work, clubby feel but occasionally compelling insights.
TEDTalks: inspirational people giving short, inspirational addresses to inspire the rest of us... very West Coast and often startlingly good.
The Apple Byte: Jokey little video survey of Apple news with a slapstick-friendly presenter.
The Skeptics Guide to the Universe: Hardcore skepticism for those tired of an increasingly pagan and scientifically illiterate world.
This Week in Google: freewheeling extended discussion on the latest emanations from Google HQ, and the philosophical and business ramifications thereof.
WNYC Leonard Lopate: pitching to those willing to listen to long, interesting and revealing interviews, with a strong humanist sensibility.