I use the umap (http://umap.openstreetmap.fr/en/map/verlengd-weekend_8367) service to visualize my GPS tracks. But I also upload all these tracks to OSM for editing purposes. Is there a service that allows you to show all your OSM tracks on a nice map like umap does?
I use http://www.mygpsfiles.com/app/ because it is so quick to use. Drag & drop your gpx tracks onto the map and it has an elevation display. It is best using full screen mode as the zoom in is limited. It does not use the osm though. If you don’t like the thick line on the track just ‘tick’ it off and then on again and it will use a thin line. I have loaded over 70 tracks at once but it almost froze so I suggest not loading any more than about 20 or 30 tracks in one hit, though it would depend on the length and detail of the tracks I guess. I am mostly cycling.
Here is a list of a few track drawing sites that use osm http://wiki.openstreetmap.org/wiki/Track_drawing_websites
My favourite so far is Bike Route Toaster