FiddlinFool -- sounds like you need a 76C! Double the memory, and it floats!
And speaking of the Magellan vs Garmin debate... I couldn't find a Magellan unit that had all the features I wanted, that I got in my 76C. And I grew up on the GPS III, and know how durable the Garmins are, so I decided to stick with Garmin. But I'd love to try a Magellan sometime, just to compare.