This is such a popular question and an even harder one to answer. The reason is that there are so many to choose from and because our voices are all so different, the microphones we should use, change from person to person.
Here’s a video on the subject of microphones:
Besides just talking about microphones, this video has other tidbits of informative goodness.
Also, as an afterthought, I have decided to go out on the limb and actually make a recommendation. If you don’t already have a microphone and you’re looking for a decent mic that will plug-n-play easily and will record well, I direct your attention to these possible choices: