Not sure if this has been posted or not - but I took my Nexus 7 to work on Thursday and wanted to test out Google Maps Navigation. To my surprise, it was able to navigate me to work (25 miles away), despite not having a wireless signal at any point during the journey.
I presume it's able to do this with a combination of locally stored maps and its GPS chip. Is this correct? 25 miles seems an awful lot of maps to download locally to the device (it's great, it's just surprising!)