How can I improve the noise cancellation on my Nexus One? Despite the highly praised Nexus One built-in noise cancellation, I need to use speech recognition in an extremely noisy environment with better noise isolation/cancellation.  Is there a so called "speech recognition microphone" that would help?  I'm not aware of the complexity or performance of the noise isolation algorithm used by the N1, is it as good as I'm going to get?
If you are working in a high noise environment, a traditional mic isn't going to help you.  Even with a noise cancelling secondary mic it will be very difficult for the equipment to pick your voice out of the noise and isolate it.  You might look into a throat mic instead, which grabs your voice by direct contact with you rather than conduction through the air.  These are especially suited for noisy environments.