I asked on the 'HUBB' for recommendations of maps for the South American countries. Apparently when it comes to the sat navs etc, Ecuador and Bolivia are poorly covered (if at all), however maps are available elsewhere as well as on OSM (open street maps). We have a Garmin Sat Nav with South American map coverage; click here for a detailed coverage map.
Personally, I do not like to have to completely rely on technology. Also, there's nothing like a good old map and compass...it takes me back to my scouting days!
Initially I was looking at the National Geographic Adventure maps as I read that they were waterproof and rip proof, however one person contacted me and said that they possibly weren't overly accurate and several other people recommended the Reise maps as they are good quality and also waterproof and rip proof (which I can now verify as I had to test one just to check!!). Obviously we may need more detailed maps of certain areas, but we intend to buy those when on the road where required. When we have wifi access we also intend to use google maps, which has also been highly recommended by fellow travellers.
If you are planning a South American adventure, then as well as Reise, the other maps that were recommended were ITMB Publishing (International Travel Maps and Books) maps. These are also described as being rip-proof and waterproof, however I have not used one myself as yet.
Once we get to putting our paper maps and technologies to the test, I will feedback on what worked, as well as what didn't.