I voted according to this:

Nice to see ,but not so useful, in some cases it is more of a hindrance than a help:
Junction view
3-D buildings and landmarks view
3D terrain view
MP3 player,Video Player,Audio book player


I rarely use:
Voice-activated navigation


IMHO completely useless:
trip planner
myTrends&trafficTrends
ecoRoute
Garmin nüLink! services(not working fine as I know)
Photo navigation
Garmin Lock
Smartphone Link services (Android app is always in background even if you are not using it,eating battery, useful features you can get with other free apps,are not free)


Useful but not fundamental:
Route avoidance
Enhanced pedestrian navigation (could be great if better made and in outdoor devices with better battery)



IMHO Fundamental,basic and halas missing in my nuvi:
Routes (real multipoints ones) from pc
POIs on navigation map

Fundamental but present
Lane assist
Lifetime map updates(bought)