For me, the audio experience went like this:
1. Digital Audio Recorder (I got the Zoom H4n. It's pro quality and has built in mic as well as multi-channel XLR inputs. XLR is the standard in the recording industry and gives you a lot more flexibility in equipment. I paid $200.00 or so.)
2. Audacity Editing Software (It's free and extremely powerful)
3. Sennheiser e835 "stick" microphone (Has a rich tone and XLR connections. About $100.00)
4. Yamaha MG10XUF 10-channel mixer (Allows multiple audio inputs, real-time mixing of levels and gains. XLR connections. There might be a repeating theme there.
I can record multiple inputs through the board directly onto my Zoom H4n. About $200.00)
5. Shure SM11 lavalier mic (This is the "clip-on" microphone similar to what you see commonly on news broadcasts etc... XLR connection. About $100.00)
Future Wish List:
1. "Shotgun" mic that I can attach to my camera. Currently looking at Rode for this.
2. Wireless lavalier mics (yes, more than one) for more flexibility in talking head style videos. Don't have a preference yet, other than it has to have XLR connection.