It also depends on how much effort you are willing to spend on the setup. You could get a USB mic and be done with it, or you can go out and look at audiophile forums and try to understand which XLR mic and DAC would best suit you.
Webcams are quite a simple matter. If you want to do a face cam in the corner of your screen, you can probably get away with using a sub-720 quality one. Otherwise you might want to look into a 1080 camera. Logitech has a pretty good range of affordable HD webcams.
Of course, if you aren't good at editing, or don't know how to check audio levels and sweeten, etc. all of the equipment in the world won't help you. If you search the rest of the discussion forums I'm sure you'll find a thread that can help you.