I've been told by a sales rep at Best Buy that it is now legal in MN to windshield mount the gps as long as it is in the lower half of the windshield. Best to check this out, but I've mounted mine on the windshield.
I have the Garmin 765T with free traffic alerts. The bluetooth is great for hands free phone. And yes, we use the mp3 player for music and talking books. The FM link to the radio is good in rural areas but there aren't many free fm frequencies available in the TC area available for satisfactory usage. I use the headphone jack to plug into the aux connection to the radio for proper performance.
It is a great benefit when in unfamiliar areas. I wouldn't travel without it. I love the lane recommendation feature especially when we are in heavy traffic.
Incidentally, Darrel and I researched the various Garmins before settling on this model.
If you belong to Costco, it is available new for around $250.
Good luck with your purchase, and whatever you get, you will be glad you have it.
