I am also looking to upgrade. I've got a Garmin 750 nuvi. I talked to Garmin on the phone yesterday ( only 10 min on hold !) and ask which one had the feature that would only show paved roads. He told me most new ones would. He also told me that with most, you can download the upgraded map program (from them) onto your computer as well as onto the Garmin. Them you can map out a route and put it on the Garmin. I found the 1490T at Best Buy for about $180 on sale. It has a 5" screen. The Garmin guy also told me that the life time upgrades are for the life of the Garmin. If it broke, I can't transfer it to a new Garmin.
Mike