On Microphones
Having recently completed my own short video which needed narration, I discovered The Hard Way that you can't treat audio as an afterthought and expect it to be good (I'm looking at [em]you[/em], MovieBob). Moore's Law has been strangely absent from audio tech, and a quality microphone that would have cost you USD$300 in the 1980's will today still cost USD$300. (I still can't figure out how you got such decent sound out of your first cheapie mic, which I recall you saying died last year.)
Mics of genuine quality tend to live in the USD$200 to $700 range (although you can easily spend far more). To make things more complicated, different mics are often optimal for different tasks -- mic X might be best for vocals, but be poor at recording acoustic guitar, for which mic Y is better.
Then comes the Connector Conspiracy [http://www.catb.org/jargon/html/C/connector-conspiracy.html], where you get to choose between 1/8" mini phono plug (no quality mic will stoop to this level), 1/4" phono plug, or XLR jack. And if you choose the XLR flavor, then you need to pay attention to whether it needs Phantom Power or not, and select your amplifier accordingly.
USB mics are starting to become noticeably okay, but measuring their audio quality is tricky, and are useless if you don't have a computer around to plug them in to.
Ultimately, I ended up testing five mics, four of them USB flavor. The first mic I tried was the mic that came with this headset [http://www.steelseries.com/us/products/audio/siberia-full/information]. It sounded a shade better than a tin can with string. Next, I borrowed a Plantronics headset from work, both with and without its USB adapter. It sounded better, but getting the mic close enough to get even a halfway decent sound made pops and plosive noises unavoidable, even with a pop filter. Next, I bought a Blue Snowball [http://www.bluemic.com/snowball/] USB microphone at Fry's and tried that. I thought it sounded thin, and it picked up room echos something fierce. Finally, I decided to have a shoot-out between a Blue Yeti [http://www.bluemic.com/yeti/] and a Zoom H4n [http://www.zoom.co.jp/english/products/h4n/] field recorder. The Zoom H4n won for a variety of reasons. One was that it sounded quite good right out of the box. Another was that I don't need to plug it into a computer to record something (although it will do that, too). And if ever I go insane and decide to upgrade, the Zoom will handle 1/4" phono and XLR jacked mics.
It is not, however, a headset affair. Quality head-mounted mics are more expensive still.
Finally, no mic of any quality or cost will save you if you over-compress the audio track. (Here I speak of digital compression, not dynamic range compression.)
Bottom line: Your difficulty in mic selection is not unique, as there is almost never an obvious best choice. It will depend on what you're recording, how and where you're recording it, and how much coin you want to drop. One thing that does appear to be true, however: Mics of genuine quality will last for years. So don't be afraid to spend a bit extra.