I should'a been keeping a closer eye on this, Yandor! Gotta say the rivers a great addition to that continent map, and personally, I like labels ^.^ I'm trying to get a good regional map into Illustrator to add a lot of roads and tiny labels; but of course, to each his own. For a whole continent a lot of labels might look a little overwhelming, whereas if you get to a national map or something about that size, more labels would be appropriate. Definitely label big rivers, important sites (battles, temples, capitals and big cities, &c. - maybe even major trade routes/roads, if that's appropriate). Bear in mind what you want to use the map for too - this looks like it's leaning towards geographic rather than a (straight up) political map, although you've started labeling non-geographic stuff like cities/capitals. Obviously you don't have to just label the geographic stuff, but too much "political labeling" might be lost in all that gorgeous geography ^.^
- Alizarine