I find that sometimes its nice to be able to see more of the map than the Montana i have can display at any one time so would like to still use the montana but view my live position on a larger screen be it a laptop or ipad. So any software that will allow me to display topo maps and OS maps. Not looking for much more than that if honest. SOmeone has once said you can save cached maps from google earth which might be cool as it owuld provide you with plenty detail but i guess you would have to "run" the whole route you plan on taking prior to going in order to save the maps required.
I think i have lots to learn still.