Spotify: Music on the go! Spotify installed quickly on my tab and it syncs the playlists that I have on my Nexus One and desktop app. Music sounds good (not perfect) on the stereo speakers. As mentioned above, some apps are not ready to be used on a large display, and Spotify is one of them. Hopefully they will fix that soon.
I will keep on testing more apps when I find the time to do so. The important apps are working just fine, so this will be encouraging for new Samsung Galaxy tab owners.