what is the best price/performace car navigation system?”
They make them in just about every grade. You can pay anywhere from $200 to $1,000 for a car navigation system (more if you wanted to have it installed in your dashboard). I personally chose the Garmin c340. I liked the large screen, the touchscreen keyboard, the ability to speak street names, the full national atlas, and the ability to route around traffic. But I didn’t actually get the traffic antenna; I just liked the idea that I might get one later (and I still might). On sale, that cost around $350. Your perfect price/performance point will depend on what you want. You might not care about the larger screen and street-name-speaking features, and only drive locally and can spend much less. I didn’t feel that I needed the cell-phone integration, the live weather reports, etc. that come on the top of the line Nuvi 680. You might consider those features mandatory.