No, these aren't GPS receivers for your amphibious vehicle. But if you've got a pickup truck and a boat trailer, they could be the units for you. Earlier today, Garmin announced the GPSMAP 378 and GPSMAP 478 (pictured at left).
These new receivers have pre-loaded marine AND highway maps for North America. Both units come with a marine mount and automotive kit, so you can use them to drive to the dock and then pop them into your boat. The GPSMAP 378 has 10-meter resolution charts for 3200 inland lakes, while the GPSMAP 478 has charts for the entire U.S. coastline, including Alaska and Hawaii.
Both units come pre-loaded with City Navigator ® NT for highway navigation, and optional XM radio weather capabilities. They are expected to be available in late May 2006 with an expected street price of $1199.99.