Hey guys!

I have a question...I have a Garmin etrex Vista Cx GPS unit and I want to get some Topo mapping software for it. What I want is to be able to SEE in the GPS unit the topo contour lines, etc. But seems like the only mapping available is the propietary Garming Topo software.
Now, seems like I have (2) options: to buy the DVD/CD topo software or to buy the SD topo micro cards...What's the pros and cons of each? Please give some pointers.

What I want is to not having to download maps to the GPS every time I head out the door. I still want to use the National geographic Topo software to plan my routes, waypoints, etc...what do you recommend??

Thanks for your help!