Don't forget the cost of DVD updates you have to pay every couple of years. That is pricey too!!! And even with all the upgrades you still will not have GPRS capability (same as in cell phones and iPhone) in your NAV, something most of the portable NAV will be equipped very soon with for unlimited POI feeds, latest updated maps, and real time instantaneous traffic updates. That was one of the "obsolete" points I was referring to before

 

You'll have to get the high end portable nav system to get all that. You wont ever get that with the cheaper ones. Not all of them are voice activated which MOST built in navs that come with the car from the factory already do. So i guess its give and take, but you cant disagree with the fact that if you could get the built in nav in the car for the same price as one withOUT the nav, You would skip on it. right?

 

Thats how I use to feel too until I actually owned a oem nav, I gave my Garmin to me wife

 

Mine does not have nav, but I have a garmin nuvi mounted via a proclip. I find myself wishing I got the oem nav all the time even though I don't use the nuvi too much.
I'll be getting oem nav on any future car I purchase so I won't have the same feeling.