GPS & Computer
How about a tablet pc like the Xplore IX104. It runs tablet windows xp so you should be able to use software like Maptech Ocean Navigator and use standard BSB charts. You can get a plug in usb GPS unit (like the earthmate) so you can keep your Garmin as a backup. The display on this unit is daylight readable (unlike most laptops)and the best part of the IX104 is it is submergable. I use an IPaq with a Navman sleeve right now in my cockpit which I am very satisfied with, but should it break I''ll replace it with something like the Xplore unit.