Mireo DON'T PANIC is a GPS Navigation app that uses TOMTOM maps and is about 10x cheaper than TOMTOM. I have tried many GPS apps and this one seems to work the fastest for a great price. The maps are saved on your SD card, so no roaming costs while on the road. The voices are loud and clear and the interface is very easy to use and clean. They also use landmarks and FOURSQUARE integration.

They currently have a christmas sale going now with 60% discount on all maps!

Also they are running a best photo competition where you can win a free WiFi camera: