I record at 16 bit 44.1 wav.
I mix down to 64 kbps mono (same as 128 kbps stereo, without the stereo, and half the media size) if its mainly talk. If it is a music podcast I would go to 128 kbps stereo. I do save a copy of the file as a wav file
I edit everything in wav. The only mp3 file is when everything is done. I have a folder for the show, and a folder for production elements (intro, outro, wooshes, etc), and folder called episodes. In the episodes folder I have a folder for each episode. I keep all the wav stuff so if I ever have to go back and edit something (which I did this week cause I offended someone when I went off topic) I was able to edit the wave file and recreate the mp3 file).