RDS-TMC GPS Gadgets and Navigation Articles

About myself - I am semi-new to GPS units. I ordered my first yesterday, a Garmin Vista HCx, though I have taken on class a few years ago on GPS units. I plan on using it mostly outdoors (I have used a map and compass for 35 years), but would like to be able to occasionaly put it on my bicycle or motorcycle so I will not get lost on city streets either. I may even use it in my car, though Mapquest and Google Maps have never failed me in reaching destinations. I also navigate roads on larger forest fires, and will be studying if I can download data for the general area before I go, arrive at the base camp, type in a lat/long or UTM of a location, and have the GPS tell me how to get there.

Question #1 - Will maps I purchase for this unit work on another Garmin in the future? After I ordered the Vista HCx, I start looking at maps and quickly became confused by the licensing. It seems if I buy a map, I am licensing the map to my current unit; it will only work on that unit. Is this true? I am hoping that this GPS unit will be replaced by a better one when the kids out of college.

Question #2 - Are the other sources of base maps besides Garmin? I read repeatedly that the biggest problem with Garmin is that you are stuck buying expensive maps. Then I read in one post on this site that mentioned GPSFileDepot - Custom Maps, Ximage hosting, tutorials, articles and more for your GPSr, that seems to contain some base maps. Are there there others?

Thanks for all the answers.