I think audio consideration is critical to video and there are very good reasons to employ an external recorder for your audio instead of the audio in the camera. Firstly, there are compromises to the audio recording in cameras, most notibly AGC (automatic gain control) and compression. You usually have the ability to turn these on or off, but you actually do want some mild compression when recording and there just isn't the level of control in most cameras that you'll need. Also, the gain circuitry in cameras will never be as clean as those in a good, dedicated recorder. I use a Denon portable solid state recorder and before I take a shot I walk into the shot and clap my hands – that way when I line up my audio and video on the timeline of my editing software I can line up the audio and video perfectly, link them together and then my audio is perfectly synced for the shot(s) I am editing. If you care about audio, you'll get better dynamic range, lower noise and better quality audio with a dedicated recorder. My 2 cents.
