I have been using a Garmin Nuvi 660 for well over a year now, and I'm very impressed with it. The wider screen is definitely worth the additional cost. The unit is accurate and the calculations are very fast. I use it all the time when driving in an unfamiliar area. With a 4 gig memory card, I have something like 50 CD's worth of music stored on it. Last fall my speedometer broke, and I just used the Garmin's display instead until I could get the car repaired.
I like the way you can type in any address, or search a database of various restaurants, airports, hotels, etc. Amazing.
The dashboard mount that has little sandbags on the base, and it stays put on the dash despite my wild driving.
I have to say that this is one thing I own that I would immediately replace if it broke.
They have a voice activated one now, which would be a significant improvement if the voice recognition works well, but I'm not sure how much it costs.
Joker