The Oregon 400 series is already discontinued by Garmin so ask for a really good price from wherever you are shopping. Replaced w/ Oregon 450 series, there is no longer a C or marine version of this model, so you have to buy the micro SD chip to get charting. I would buy the 450t loaded w/topo maps, for your hiking, and then the chip for your boating needs. The 76 series requires a download from the CD/DVD for maps/charts. If you don't want charts/maps the 76 is a whole bunch less expensive.