Ok just to stop the thread, this has been discussed countless times before.
Anyway, the conclusion is allways ditch Delorme's Street Atlass. Allthough accurate in some areas, very inaccurate in most. Most people here are using iGuidance or Routis now. This software has proven to be incredibly accurate, instant re-routing, voice guided and designed for touchscreen use, but can also be used with non-touch screens.
Allthough co-pilot is nice it is not cheap. Buy it new for about $200.00. iGuidance new is only $100.00 and has all the feature of co-pilot and more.
As far as the GPS unit it self goes, I do not know. I am using the BU-303 GPS reciever on ebay. Bought it 2 years ago for $80.00 it now goes for about $50.00. It is great, never had any problems. It is mounted on my roof using it's magnetic base, because yes it is water proof. It has been there for about 8 months now. My reasonf or placing it there was simply for better view of the sky (more sattelite coverage).
Just my 2cents
