There are a Lot of Podcasts
Podcasts are a form of communication that is infinitely variable within the limits of their definition. Podcasts can only be podcasts, but podcasts can be just about anything you can imagine.
Here are a few links to lists of podcasts. Each of these "best of" lists is varied, each pod appealing to different tastes of different listeners, and despite these lists offering hundreds of options, there are still hundreds (or more likely, thousands) more to discover and listen to.
I have my own suite of most-listened-to podcasts – some news, some entertainment, some both – but I also have shifting interests and attention. I'll take a break from a certain news podcast and trade it in for a true crime series (something I can bond with my girlfriend over). I have this infinite variety available to me as long as I have an Internet connection.
My shifting interests put me in a tricky position to choose a topic that's general enough to keep a show going but also specific enough to keep my own attention on it. It's difficult to imagine a podcast that I would host that I would be still be doing in a year from it's inception (let alone a month or two).
In an effort to experiment with the format, keeping it relative and meaningful to me, I would ask friends and family to have semi-interview style conversations about themselves. I could do that, and I'm somewhat confident that I could convince the people, those who call themselves my friends, to join me.