You know, that's why I opted for a third-party GPS unit...I eventually bought a TomTom ONE.
IMHO, all automakers charge an outrageous amount for a built-in GPS (seems like $1,500 to $3,500 is the going rate), and then expect you to purchase updates every so often at $100 to $200 a pop. My TomTom may not be integrated into the dash, but for $280 bucks I have a pretty nice system...AND I can update my own points of interest from my PC. Not to mention that I can move it from my Jeep to my company car, or to rental cars...used it in Orlando last week, and it was VERY nice. Plus, if I lose or break it in a couple of years, no big deal.
I wish I had an OEM GPS units, but until they come down in price for both the original purchase and for the updates, I'm sticking with a portable.