What I've done with my Ford Ranger Edge Truck
1) XM satelllite radio with a window mount antenna on my windshield
2)Bull Dog car alarm system With Dome light superviserion (dome light comes on when you disarm the alarm system)
3)Automatic dome light Night sensor (Dome light only comes on when there is low outside ambient light)
4)Third brake light flasher flashes the hight mount stop light at a pre programed rate (high mount stop light flashes when you apply the brakes so others can see you better before you come to a complete stop.
5) puddle lamps on the under side of the truck come on when the dome light is on.
6)Dome & puddle light timer theather style (when a door is closed the timer comes on and keeps the lights on around 20 secounds then fades down the lights untill the lights are off completely.
7) Parking brake beeper the beeper beeps when I apply my parking brake for a few seconds after I apply the brake to be sure that I set the parking brake.
8) Backup alarm system (home-built)
9) Remote start starting system 
10) Daytime running fog lights
11) LED floor lights
12) LED side blinker lights
