I got the garmin 478 for xmas...a little on the expensive side (for an auto) because it's a car and a marine gps. The unit on our boat is a little outdated so it's a great back up and actually shows a lot more detail than our current one. Our main unit froze up on the way to hatteras running the sound so we used the other- worked great. If you need a boat backup this an awesome choice.
Have a Lowrance Iway 500c in wifes Titan and I use my laptop with Garmin usb in truck as I use all the different softwares by Garmin depending if I take the laptop on the road or water. I sell more Garmin Nuvis then anything though and no complaints about them.