I played around a bit with OpenLayers and built a map that does pretty much everything I want. The map is available on http://osm.cdauth.de/map/. You can view OpenStreetMap data (Mapnik, Osmarender, Cyclemap, OpenStreetBrowser, Minutely Mapnik, and Hiking map; PSV- and piste map following soon), TeleAtlas data (Google Maps), Navteq data (Yahoo maps) and other geo data (OpenAerialMap, Relief map). It saves the current view in the URL hash part, so you always have a Permalink in your address bar. The OpenStreetMap Namefinder is also implemented. You can create Markers just by clicking on the map. My map might however still be pretty buggy at the moment.