I use navit, it's fantastic. easy to use with touch but can be used with a keyboard and mouse, works faily great in the car with rout auto planning. it's in the repo. snag is with navit you have to edit a xml file to configure it/setup. to tell it where your map data is and to enable UI bits, I find it worth it. the config is farly self explanatory but theres help on the wiki.
theres a java editor for the navit gui UI and config http://sourceforge.net/p/navitconfigurat you can get your mapdata here http://maps5.navit-project.org/ select the area you want and download it. you'll then have that area available for off-line use. oh yea theres no uk postcode support due to evil royalmail and it keeping the database as knowledge for the privileged (ie com's that can pay the fees). wikileaks has a copy of the data base, that would do most of the job i think~ but I don't know if anyone has done anything with it. over time there leaked copy will become out of date due to the official database changing. navit is improving and the package in the repo becomes out of date. but I believe you would have to compile it your self to get a newer version unless someone's done it. Personally I just get on and use of the one in the repo.
