Since I planed on putting these maps on the web I needed to find some data with a fairly nonrestrictive license. The data set at http://naturalearthdata.com seemed ideal. As the home page puts it:
“Natural Earth solves a problem: finding suitable data for making small-scale maps. In a time when the web is awash in geospatial data, cartographers are forced to waste time sifting through confusing tangles of poorly attributed data to make clean, legible maps. Because your time is valuable, Natural Earth data comes ready-to-use.”
This sounds like exactly the position I’m in. It has added advantages that they generalized the data nicely so that the ocean always touches the land, rivers line up with borders etc.