Car Satellite Navigation
Satellite navigation systems for cars now offer colour 2D and colour 3D mapping display, voice and visual guidance, automatic re-routing if you make a wrong turn and full post code searching as standard. Some units also have the ability to play MP3 music, store and display pictures and receive incoming mobile phone calls by bluetooth and receive TMC based traffic alerts, although these last two options can sometimes play havoc if your trying to navigate at the same time!
Moreover, there is an increasing range of Points Of Interest (or POIs for short) with things such as petrol stations, hotels and restaurants, with further options for tourist guides, currency converters and even language translators all clearly indicated.
Speed Camera Alerts
The most desirable feature - for the UK market at least - is the speed camera data. The best manufacturers to choose for these features are Road Angel and Snooper who actively update their databases everyday and offer systems that will alert you to speed cameras, even when you're not using the navigation option.