Oftentimes, handheld users will load both highway and topo maps to their unit. Garmin handhelds will show the highway maps by default. The highway map (City Navigator or City Select) for an area must be turned off before you can see the topo map. This is especially problematic when you have a lot of maps loaded and you don't know the name of the map for your current location.
In the past, I've laboriously scrolled through long lists of highway maps, deselecting each one until contour lines appeared on the map. But there is a simple solution. The instructions below are for the Garmin 60CSx, but I'm hoping this works for the eTrex series too. Perhaps someone can verify that and comment below.
From the map screen, press Menu, then Setup Map, and scroll over to Map Setup - Information. You'll see your list of loaded maps with a check mark next to each one. But rather than de-selecting them one by one, press Menu again and you'll see two choices - Hide City Select (or Navigator) and Hide US Topo, as shown in the image. Pretty cool, huh?
Thanks to Hogrod on Groundspeak for this tip.