I have a nüvi 765T. Got it last year from Costco. I think I paid around $200. It's got the free FM traffic and a 4.3" wide screen. It's OK but I've been disappointed with some aspects of if.
First, the touch screen is pretty bad. I'm always making corrections because I'll hit one letter but get another. Sometimes it's way off. I'll hit 'J' and get a 'T'. I've also had an issue with directions coming a little late 3 or 4 times over the last year or so. Once, it told me to take an exit just as I passed it and I ended up going over the George Washington Bridge. That little slip cost me $8. Other times, it just cost me a little time. The only other issue is the traffic is sporadic. Sometimes it's spot on and will direct me around an incident. Other times, I never see traffic that it's reporting. I'm also a little disappointed in how often it loses the traffic signal. It relies on an FM signal that isn't everywhere. It's kind of like 3G on cell phones. Sometimes it's there. Other times it isn't.
I looked for an additional car cable but since it has the traffic receiver built into it, it costs $80. It will work with a non-traffic cable if you are willing to go without traffic in a 2nd car... or just don't try to hide the cable under the dash.
Not all is bad though. The maps are great and most of the time, very accurate. Start up and recalculation times ar quick. The screen is bright and sharp but it can get washed out in direct sunlight.
My favorite feature is the FM transmitter. I added an 8 gb SD card full of music. When I drive out to my sisters house in PA, I use the MP3 player as soon as I start loosing my normal radio stations. It works great so long as there isn't any interference from nearby stations.
If you can put up with it's quirks, it's a good unit for the money... if you can get it for $200 or less...
FYI - MS will be discontinuing MSN Direct
in 2012. I would avoid units with this feature.