-- Last Updated: Mar-20-13 4:10 PM EST --
I use both the Topo and the Blue Chart, depending on the trip. They complement each other.
Another option that is available for the 78 that I am using more and more, is the BirdsEye Satellite Imagery ($30.00 annual subscripton). This allows you to load satellite images right to your handheld and is very useful for small areas where you need maximum detail (although the images can appear dark on the small GPS screen).
For route planning, you will probably want some software. I recommend Garmin's Homeport application (available online).
It takes some time to get proficient with all these tools and maps, and of course, the GPS itself.