I listen to many podcast but I'll keep my list constrained to tech topics in two categories. Coding (software) and hardware. Both in order best to least best. (I like them all so I don't want to say best to worst)
1) dotnetrocks The best programming focused show there is. Awesome topics that are not always focused on dot net topics.
2) codenewbie duh! As if you don't know what this is about already
3) Hanselminutes covering all areas of software development and beyond. Great show where I discovered the code newbie site when Saron was interviewed by Scott.
4) Windows Developer Show mainly focused on the windows software development. Great information here about upcoming projects in the Microsoft world.
1) The Tech Report covers all areas of hardware including motherboards, CPUs, GPUs, SSDs, laptops, phones etc
2) PCPerspective very much like The Tech Report but I list this one lower because sometimes some of the co-hosts can get a little too silly for my taste.
3) anandtech this one would actually be at the top for me but the shows are not released regularly and now Anand has taken a job at Apple so the future of the podcast is in serious jeopardy.
Bonus section* tech news
1) Windows Weekly This show covers all the latest news from Microsoft. Co-Host Mary-Jo Foley is probably the classiest woman in tech journalism. Worth a listen just for her.
2) The tech informist In the first half of the show a tech journalist is interviewed and the second half the tech news is covered.