I did a lot of research on this topic, and here are the different programs I using (including various hardware).
I am on the iOS (Apple) side of things, I can not comment on the android.
1. GPS. I use Navigon app - it's a fantastic GPS.
2. I bought all 3 currently available iOS programs that use the OBDC II port found in our cars. I purchased the FuzzyCar, Rev, and DashCommand. Of the 3 I found Dashcommand to be the best. Torque is not available on IOS. The only problem is that you will need to purchase a wifi dongle that has to be plugged into the OBDC port. I purchased PLX Industries wifi plug. I chose this one because there is an on and off switch since OBDC is always powered, and can drain your car battery. I permanently installed this thing in my car and find it to be a great toy to play with. All sorts of useful information, from air flow to instant mileage.
3. Radar Detectors. for use with Valentine 1 there is the RadarActive app that can interface with V1. It can also be used standalone. It has a database of all the speed and red light cameras. It's good.
4. Radar Detectors part II. I did not like the way Valentine V1 was hanging off the windshield (sooooo visible to everyone) that I bought the passport escort remote radar detector 8500ci plus. Works reasonably well, but I think V1 has more range.
5. TrafficView: this is a nice app that gives you access to traffic cameras. Can be extremely handy.
6. Record Keeping. I currently use 2 apps to keep track of my maintenance and mileage. I use fuelly - it's a great idea. But I also use Car Care, it's also pretty good.
Yes, I probably went too far with all this stuff.
If anybody is interested, I can post some pictures of what all this stuff looks like inside my car.