Audio in Captivate 5.5 - Best Hardware?

Nowadays I prefer to use good quality USB podcasting microphones instead of headset mics.  The diaphragm in a headset mic is tiny by comparison and you can never get the bass response you want.

I use Blue Yeti, Blue Snowball, and Rode Podcaster.

If you want to enhance the audio, you really need to use an audio editing package.  For free you can get Audacity.  For money, go with Adob Audition.  Better yet, buy the E-Learning Suite because after buying Captivate and Audition separately you could almost have afforded the suite.