One important one: the www.openstreetmap.org page really needs to show more and "better" (=more aluring/useful) maps. See osm.org/user/Buadhai/diary/8208

And an interesting one: representing race tracks in OSM. The two major examples in the Netherlands are examples of the "shambles" that exists in this area. Well, at least they are on the map already. See osm.org/user/kevjs1982/diary/8217