9. Google Maps
It's probably useless to explain how extremely useful this application is. That's why it's on number 9 in our list.
Google Maps for Windows Mobile can show the unbelievable possibilities of the combination of integrated GPS and an internet connection on you cell phone. Not just for finding directions but mainly for Google's enormous database of address information. No matter where you are, type in 'pizza', or anything you feel like having, in the search box in Google Maps. You get an instant satellite/street image of your location and pin points of nearby search results. Several options? Tap on one of the pin points for more details and tap on the website link to see if you like the menu and the images of the interior. Good enough? Directly tap on the phone number in your Google Maps pin point to make a reservation and then let Google Maps calculate the fastest route to it. Even if you don't have integrated GPS in your phone, it can still use a (much less accurate, +/- 1000 m) positioning by using relative distance to mobile towers. Google Maps Mobile is an absolute must-have and real example of technology in it's most useful way.