If anyone is looking into buying a Garmin Nuvi, one must have item that I highly recommend a Nuvi owner to get is their friction mount, seen here:
Amazon.com: Garmin Portable Friction Mount for Nuvi, StreetPilot I Series & C530, C550 (010-10908-00): Electronics
I got mine from Best Buy in store because a few weeks back it was on sale for $29.99, plus I had a $5 rewards coupon to use, but Amazon's price is really nice, especially considering free shipping is included and you don't have to pay tax, not to mention they're reputable to deal with.
I've had my Nuvi 660 since Xmas and what you will eventually deal with is a problem with the suction windshield mount that comes with the unit. It will eventually not hold its suction and the rubber leaves behind a baked on ring on your windshield that is quite difficult to remove completely.
I believe it's a design flaw, and according to other posts I've read it seems that Garmin's customer service also acknowledges the problem too because they will send you a new suction mount if you call. The problem though, is that it will begin failing again.
For many months I was dealing with licking the rubber suction or applying 50/50 ipa to help the mount stick, only for it to fall off during driving or fall out by the next time I got in the car. The longest it would stay on the windshield was less than 24 hours.
The only regret I have now is not buying this product sooner. If you looked at the Amazon link I posted, you will see that out of 73 reviews, it has an amazing 5 star rating. One reviewer had a really good comment about how having a windshield mount just attracts unwanted attention. Even if you hide your nav in your glovebox, the thief will just assume correctly that you're hiding it there. And if you happen to take your nav with you everywhere, then the thief would have still broken into your car.
With the friction mount, when I get out of the car, I simply put the mount on the floor, or my center console. It also hides my iPod from view because often times I'm too lazy to hide my iPod. Unless someone were to come up to your car and start peeking around, they wouldn't be able to tell just by looking at your windshield whether you were hiding something valuable or not.
Plus, part of the benefit of having a portable nav is being able to use it from car to car. It's much easier to just place the friction mount on any dashboard and go, versus getting the windshield suction mount to stick correctly, and then deal with having to clean off the windshield once you remove it.
Also, keep in mind that in California it's illegal to mount a navigation to your windshield so by using this you're abiding by the law.
I know this posts sounds like a freaking advertisement LOL, but I'm in no way affiliated with Garmin, Amazon, or Best Buy (unless you want to count the time I worked as Xmas help years ago.) I wanted to post this because of the frustrations I had for many months dealing with the original suction mount and I know if someone else has a Nuvi out there, most likely they're experiencing this same problem. Save the time and headache and just buy the $30 friction mount. You won't regret it.
BTW, I was skeptical as to how the friction mount could stay on your dashboard. It does not slide at all and I've taken some fairly sharp turns in the car. The only downside to this product, is that it's slightly bulky but I really do not think that will stop anyone from liking and using this type of mount instead.