That is why I am upset that my '07 Mercury came map discs that were already two years old, 2005 editions. And Ford has no plans to ever update them.

I've fumbled around with the portable NAV units in several cars and I'm really glad to have the NAV integrated into my TCH now!
I really like my TOMTOM devices but I was always worried about them being stolen or falling off the windshield. Wires hanging all over the place was also a real pain.
The integration is worth the few bucks of depreciation to me.

The portable NAV units do have their place however. I still use mine when rent a car on trips.

Toyota "could" have given us detailed energy information without requiring a NAV. Prius's have a touchscreen and energy info with or without a NAV. Portable NAVs are but a pain in the rear to secure from theft everytime you leave the vehicle unattended. Built-in NAVs are worth it just for the security against theft.
As for updates, even Garmin is producing very few database updates on my spare 4 year old portable. It's been well over a year since the last update and nothing on the horizon.

If you have one portable nav stolen the cost will be more than the depreciation of a built in unit plus you will have to deal with a broken window or some other damage.

With the built in unit, I just turn the car off and leave. There is still a risk of break in to steal the built in unit, but it is much less than a portable.

I also got mine because of the energy screen and would have probably paid 1/2 the price if I could have gotten it without the nav, but now that I have the navigation I find I use it for places I know where they are just for the time estimates even though they are not really accurate.

Almost all options pay off poorly on resale, and the best car to buy for resale is the base modle with no options.

ag4ever, I agree with you that all options pay off poorly on resale, however, many used car shoppers will pass by a base model used car in favor of the more fully equiped one. That reduces the audience for the base model, thereby reducing, by some unknown amount, the value of that base model.

If you have the built-in nav stolen, it will be more than just the part-dept's retail cost for a replacement, you will have to deal with a broken window, broken dash trim, and cut wiring harnesses. Thieves who specialize in stealing factory "radios", don't take their time, nor are they careful.

That's strange. I have a six year old Garmin StreetPilot III and I've been getting almost yearly map updates. My last update was July 2006. I paid $75.00 for this last update. (Previous years updates were $150.00) I'm expecting the next update sometime this fall. http://www8.garmin.com/unlock/update.jsp

That's about what I pay for the updates to my "old", and long discontinued, Garmin.

However, that does bring up another option. If you use Verizon for your cell phone, they offer their cell phone based Navigation application called "VZ Nav" for $10.00 per month. This way, you have daily updated maps and database. $10 per month is $120 per year, which is in the range of just the updates (no hardware) being between $75 and $150 per year.

True, that's an option I had not thought of.
It wouldn't work for us as it requires a GetItNow compatable phone.
Our two Verizon phones are a Kyocera 7135 (Palm PDA phone) and a Motorola StarTac 7168 (pre-GPS phone). Plus I'm not sure if it would work in Canada (it might depending on how it gets its data) or in Japan (it definitely would not), while my current GPS will.

You might find that one will soon be having to replace any non-GPS (actually non-e911) cell phones. The FCC has already banned activating them. Plus, analog service (again thanks to the FCC) will be going away in early 2008. I think that would be a "double whammy" for the ol' StarTac's, no?

Also, while a US cell phone based Nav application might not work in Japan, I don't know very many people planning on driving over to Japan either. At least I don't. So, the built-in Nav system in my hybrid isn't going to do me much good in Japan either.