I was going to say that Germany has many more good-quality regional broadcasters than the US does. But actually, if you include large-city stations, we have a fair range of choices too.
NPR (#1 above) is the primary nationwide public radio network in the US. I can also recommend it, but there are also other possibilities.
If you mean North America in a general sense, there's always Canada (CBC), which also has a wide selection, including a program for English learners.http://www.cbc.ca/podcasting
PRI (Public Radio International) is (as I understand it) a separate US organization that also produces a variety of public radio programs, including some popular ones broadcast over NPR stations.http://www.pri.org/pri-podcasts.html
American Public Media is another separate US organization that produces shows such as Marketplace, a daily center-left business/economic news show; and Garrison Keillor excerpts such as the Writer's Almanac (daily 5-minute feature on writers and poets whose birthday it is today) and the News from Lake Wobegon (from Prairie Home Companion, which is available elsewhere, I think).http://americanpublicmedia.publicradio.org/po...
One of its shows I especially like is Performance Today, with interviews and performances of classical music.http://performancetoday.publicradio.org/piano...
Pacifica is a left-wing/progressive radio network (very left-wing for the US, probably ho-hum for Germany).http://www.pacifica.org/programs/podcast/inde...
Democracy Now is one of the best-known Pacifica programs; I find it rather dry and earnest, but it sometimes covers obscure (to us) news in the southern hemisphere.http://www.democracynow.org/podcasting
If you're just interested in sampling different regions, many large-city stations or regional networks have their own podcasts. Try just searching on something like "public radio" + "podcasts" + [city/region].
Some examples, not all of which I've checked out:http://minnesota.publicradio.org/radio/podcasts/
(Minnesota Public Radio)http://www.wpr.org/webcasting/audioarchives_d...
(Wisconsin Public Radio)http://www.chicagopublicradio.org/Tools.aspx
(New York City)http://www.kqed.org/video-audio/podcasts/
Apparently many major newspapers now also produce podcasts, e.g.,http://www.nytimes.com/ref/multimedia/podcast...
(New York Times)http://www.washingtonpost.com/podcasts
(Los Angeles Times)http://www.miamiherald.com/podcasts/
That ought to tide you over. (-;