The client that I have using AC has Dragon Medical 10 running over remote desktop so dragon is only loaded on the server. They have four providers running it simultaneously and have no troubles with Unidirectional Dynamic Microphone from Radio Shack plugged into the sound card and mounted to a flex goose mic stand "its like 15 inches" mounted to the KB stand on the workstation.
We went this route because they have 9 workstations and patients might mess with them when left in the room unattended. We did tested a number of mics even ones from Audio Technica and found that you don't need that crazy when it comes to mics.
Hope this helps.
-Dog
