Let the hive mind of Engadget get that for you.
"I've found myself using my PC for a lot of conversations lately, and I'm also considering recording a podcast to share with anyone who will listen. There are tons of USB headset / microphones out there, and I'm hoping someone has some solid recommendations based on experience. I'll consider both headsets and standalone mics, by the way, but I'd like to keep the bill under $100 if possible. Help!"
Mac Mini with Plex
How do you get multichannel sound (DD/DTS, etc) out of a Mac Mini?
The Mac Mini outputs optical audio. You can use a toslink to miniplug cable (http://tinyurl.com/6eqlsc) for the audio and a DVI->HDMI cable (http://tinyurl.com/6j5o2j) for video.