Nokia N8-00

I have no idea if Google Maps will have voice guidance available for the N8 but have you tried downloading the maps and guidance onto your N95? (not sure if it's supported on that phone or not.) I did it with my 5800 and it was excellent. It never had any problems (because it didn't go online) and always had all the routes (update the maps every few months if need be, though I think once a year would be enough.)
I've stowed away my 5800 for the N900 and the one thing I sorely miss is the Maps app for Symbian. It truly was just as good as a standalone.