If you're looking for even bigger and better things, there's the nüvi 1800 family. The nüvi 1820 checks in with a 4.8-inch WVGA panel, a Linux-based OS, Bluetooth handsfree support, WiFi, lane assist, a traffic receiver, text-to-speech and a few features not found on your common PND. We're talking about a full-fledged web browser (with YouTube support), multimedia player, access to email, internet radio streaming and even video streaming. Of course, you'll have to provide the web access, but if you've got a MiFi or the like riding shotgun in your ride, you can keep this bad boy connected throughout the trip. Also of note, the nüvi 1860 packs all of the aforementioned goodies but throws in a 3 megapixel camera with geotagging for good measure. Garmin doesn't bother to mention pricing details on either of the 18xx units, but we get the impression that both will sticker for well over the $500 mark.
Update: That $500 sticker on the 1690 will include two years of connected services -- not perfect, but a solid gesture nonetheless.